bluuebunny/crossref_metadata_2025 huggingface dataset:
Carbon dioxide fixation as a central redox cofactor recycling mechanism in bacteria
Authors: McKinlay James B. , Harwood Caroline S.
Published: June 2010

The Calvin-Benson-Bassham cycle (Calvin cycle) catalyzes virtually all primary productivity on Earth and is the major sink for atmospheric CO
2
. A less appreciated function of CO
2
fixation is as an electron-accepting process. It is known that anoxygenic phototrophic bacteria require the Calvin cycle to accept electrons when growing with light as their sole energy source and organic substrates as their sole carbon source. However, it was unclear why and to what extent CO
2
fixation is required when the organic substrates are more oxidized than biomass. To address these questions we measured metabolic fluxes in the photosynthetic bacterium
Rhodopseudomonas palustris
grown with
13
C-labeled acetate.
R. palustris
metabolized 22% of acetate provided to CO
2
and then fixed 68% of this CO
2
into cell material using the Calvin cycle. This Calvin cycle flux enabled
R. palustris
to reoxidize nearly half of the reduced cofactors generated during conversion of acetate to biomass, revealing that CO
2
fixation plays a major role in cofactor recycling. When H
2
production via nitrogenase was used as an alternative cofactor recycling mechanism, a similar amount of CO
2
was released from acetate, but only 12% of it was reassimilated by the Calvin cycle. These results underscore that N
2
fixation and CO
2
fixation have electron-accepting roles separate from their better-known roles in ammonia production and biomass generation. Some nonphotosynthetic heterotrophic bacteria have Calvin cycle genes, and their potential to use CO
2
fixation to recycle reduced cofactors deserves closer scrutiny.
Micromagnetic computer simulations of spin waves in nanometre-scale patterned magnetic elements
Authors: Kim Sang-Koog
Published: June 2010

Current needs for further advances in the nanotechnologies of information-storage and -processing devices have attracted a great deal of interest in spin (magnetization) dynamics in nanometre-scale patterned magnetic elements. For instance, the unique dynamic characteristics of non-uniform magnetic microstructures such as various types of domain walls, magnetic vortices and antivortices, as well as spin wave dynamics in laterally restricted thin-film geometries, have been at the centre of extensive and intensive researches. Understanding the fundamentals of their unique spin structure as well as their robust and novel dynamic properties allows us to implement new functionalities into existing or future devices. Although experimental tools and theoretical approaches are effective means of understanding the fundamentals of spin dynamics and of gaining new insights into them, the limitations of those same tools and approaches have left gaps of unresolved questions in the pertinent physics. As an alternative, however, micromagnetic modelling and numerical simulation has recently emerged as a powerful tool for the study of a variety of phenomena related to spin dynamics of nanometre-scale magnetic elements.

In this review paper, I summarize the recent results of simulations of the excitation and propagation and other novel wave characteristics of spin waves, highlighting how the micromagnetic computer simulation approach contributes to an understanding of spin dynamics of nanomagnetism and considering some of the merits of numerical simulation studies. Many examples of micromagnetic modelling for numerical calculations, employing various dimensions and shapes of patterned magnetic elements, are given. The current limitations of continuum micromagnetic modelling and of simulations based on the Landau–Lifshitz–Gilbert equation of motion of magnetization are also discussed, along with further research directions for spin-wave studies.
Energy demand during exponential growth of Octopus maya: exploring the effect of age and weight
Authors: Briceño Felipe , Mascaró Maite , Rosas Carlos
Published: June 2010

Briceño, F., Mascaró, M., and Rosas, C. 2010. Energy demand during exponential growth of Octopus maya: exploring the effect of age and weight. – ICES Journal of Marine Science, 67: 1501–1508. Recent work has reported changes associated with physiological, morphological, and behavioural adaptation during the absorption of yolk reserves. The holobenthic endemic species Octopus maya was used to explore the energy supply needed from the food intake (I; J animal−1 d−1) to supply the rate of production energy needed for body mass (P; J animal−1 d−1) and respiration rate (R; J animal−1 d−1) as a function of weight and age during the exponential early growth phase of the animal. Individually housed juveniles from hatching (1 d) to 105 d after hatching (DAH) were used, with the age and weight known, and the relationship between oxygen consumption (VO2; mg O2 animal−1 d−1) and weight (g) was established. Projections of I, R, and P as a function of age (Z) were made. The food intake destined to supply body mass production (%P/I) and respiration rate energy (%R/I) was analysed for an extended age range of 1–150 DAH. When O. maya juveniles hatched, they had a greater requirement for R than for P from the food intake, 61% (%R/I) and 13% (%P/I), respectively, suggesting high metabolic cost associated with post-hatching (during yolk absorption). Within the period where ZR > ZP (1–105 DAH), there was sufficient metabolic energy to satisfy the demands for sustaining exponential body mass production. The age at which %R/I = %P/I delimits the point where P cannot increase for reasons of metabolic constraint.
Successful Presentations and GP Registrars
Authors: Ridgway George
Published: June 2010

All the world's a stage, And all the men and women merely players: They have their exits and their entrances; And one man in his time plays many parts. Shakespeare, (1600) As You Like It, Act 2, scene 7.

Oral presentations may be thought of as performances. At the heart of all performances should lie the question: Am I serving my audience well and what can I do to raise my standard? To gauge if your audience enjoyed and valued your presentation, you can listen to their applause and remarks made in the discussion section in addition to reading your peers' review. For your oral presentations most of this feedback may be captured through a well designed evaluation form.
Laryngeal Cancer
Authors: Anderson Ross , Rigg Carolyn , Ellul David , Robson Andrew
Published: June 2010

Laryngeal cancer is a disease that usually presents with hoarseness. It is most common in older people and those of lower socio-economic classes. Understanding the warning signs and symptoms can help in making an early referral to the ear, nose and throat (ENT) specialist. This article aims to provide an overview of the ways in which laryngeal cancer can present, its treatment and problems that are sometimes encountered.
Bacterial Skin Infections
Authors: Pye Laura
Published: June 2010

In the UK, 15% of consultations in primary care relate to problems with the skin. Bacterial skin infections are common and range widely in their size, severity and variety of skin changes produced. This article aims to provide information on the clinical presentation and management of bacterial skin infections including folliculitis, furunculosis, impetigo, ecythma, staphylococcal scalded skin syndrome, cellulitis, erysipelas and necrotizing fasciitis.
Inhaled Hydrogen Sulfide Protects against Ventilator-induced Lung Injury
Authors: Faller Simone , Ryter Stefan W. , Choi Augustine M. K. , Loop Torsten , Schmidt René , Hoetzel Alexander
Published: June 2010

Background

Mechanical ventilation still causes an unacceptably high rate of morbidity and mortality because of ventilator-induced lung injury (VILI). Therefore, new therapeutic strategies are needed to treat VILI. Hydrogen sulfide can induce hypothermia and suspended animation-like states in mice. Hydrogen sulfide can also confer antiinflammatory and antiapoptotic effects. This study investigates the organ-protective effects of inhaled hydrogen sulfide during mechanical ventilation.

Methods

Mice were ventilated with a tidal volume of 12 ml/kg body weight for 6 h with synthetic air in the absence or presence of hydrogen sulfide (80 parts per million) and, in a second series, at either mild hypothermia or normothermia. Staining of lung sections determined the degree of lung damage by VILI score and apoptotic cells. Bronchoalveolar lavage fluid was analyzed for the cytokines interleukin-1beta and macrophage inflammatory protein-1beta and for neutrophil accumulation. Heme oxygenase-1 and heat shock protein 70 expression were assessed in the lung tissue by Western immunoblot analysis.

Results

Mechanical ventilation at both hypothermia and normothermia led to a profound development of VILI, characterized by pulmonary edema, increased apoptosis, cytokine release, neutrophil recruitment, and up-regulation of the stress proteins such as heme oxygenase-1 and heat shock protein 70. In contrast, the application of hydrogen sulfide during ventilation at either mild hypothermia or normothermia prevented edema formation, apoptosis, proinflammatory cytokine production, neutrophil accumulation, and inhibited heme oxygenase-1 expression.

Conclusions

Inhalation of hydrogen sulfide during mechanical ventilation protects against VILI by the inhibition of inflammatory and apoptotic responses. Hydrogen sulfide confers lung protection independently of its ability to induce mild hypothermia during ventilation.
Sociodemographic and Dietary Risk Factors for Natural Infant Intussusception in the United States
Authors: Johnson Brian , Gargiullo Paul , Murphy Trudy V , Parashar Umesh D , Patel Manish M
Published: June 2010

Background:

In 1999, a US case‐control study demonstrated a strong association between intussusception and a rotavirus vaccine (Rotashield). However, because most (87%) cases were not temporally associated with vaccination, we reanalyzed these data to assess risk factors for intussusception cases unrelated to Rotashield.

Patients and Methods:

Case‐patients were infants with intussusception between November 1998 and June 1999. Controls were matched by age and hospital of birth. Sociodemographic and feeding practice data were collected through parent and provider interviews. Conditional logistic regression was used to identify risk factors for intussusception, controlling for exposure to Rotashield <21 days before intussusception.

Results:

Four hundred twenty‐nine cases and 1763 controls were enrolled. Among case‐patients, 372 (87%) had not received Rotashield within 21 days before intussusception. After adjusting for recent Rotashield administration, factors associated with intussusception included male sex (odds ratio [OR] 1.7; 95% confidence interval [CI] 1.3–2.2), Hispanic (OR 2.1; 95% CI 1.4–3.2) or black (OR 1.8; 95% CI 1.2–2.7) race/ethnicity, and Medicaid enrollment (OR 1.5; 95% CI 1.1–2.0). Feeding practices modified the risk of intussusception. Interaction was found between introduction of solid food (ISF) and type of formula consumption. Using breast milk as the referent group, infants with ISF for at least 5 weeks who consumed soy milk–based formula had a lower risk (OR 0.26; 95% CI 0.1–0.7) and infants without ISF who consumed cow's‐milk formula had an increased risk (OR 2.33; 95% CI 1.4–3.9).

Conclusions:

Risk of intussusception among US infants varies based on sociodemographic characteristics and feeding patterns.
Constipation‐associated and Nonretentive Fecal Incontinence in Children and Adolescents: An Epidemiological Survey in Sri Lanka
Authors: Rajindrajith Shaman , Devanarayana Niranga Manjuri , Benninga Marc A
Published: June 2010

Objectives:

Fecal incontinence (FI) has a great effect on quality of life of children with the condition. Epidemiological data related to FI from developing countries are sparse. Studies differentiating functional nonretentive and retentive (constipation‐associated) FI are not available.

Patients and Methods:

This was an island‐wide, cross‐sectional study. Information was collected from children (ages 10–16 years) from 5 randomly selected schools in 3 geographically and socioeconomically different provinces in Sri Lanka, using a validated, self‐administered questionnaire. FI was defined as defecation into places inappropriate to the social context, at least once per month, for a minimum period of 2 months. Constipation was diagnosed using Rome III criteria.

Results:

A total of 2770 questionnaires were distributed and 2686 (97.0%) were included in the analysis. Of them, 55 (2.0%) had FI (mean age 11.96 years, SD 1.59 years, 43 [78.2%] boys). Forty‐five (81.8%) had constipation‐associated FI and 10 (18.2%) had nonretentive FI. The highest prevalence of FI was seen in children aged 10 years (5.4%). A significant negative correlation was observed between age and the prevalence of FI (r = −0.893, P = 0.007). FI was significantly higher in boys (boys 3.2%, girls 0.9%), those exposed to recent school‐ and family‐related stressful life events, and those from lower social classes (P < 0.05).

Conclusions:

FI is not uncommon among children and adolescents of 10 to 16 years of age in Sri Lanka with a male predilection. Some predisposing factors, such as exposure to stressful life events and being bullied at school, which are similar to those described in the literature for FI, could be clearly recognized.
Isolation of Aurantimonas altamirensis from pleural effusions
Authors: Téllez-Castillo Carlos J. , González Granda Damiana , Bosch Alepuz María , Jurado Lobo Valme , Saiz-Jimenez Cesareo , Juan José Luis , Millán Soria Javier
Published: June 2010

Here we report two cases of isolation of Aurantimonas altamirensis from pleural fluid and blood. The strains were identified by 16S rRNA gene sequencing. A. altamirensis appears to be a rare pathogen involved in unusual infectious processes, and must be isolated and studied at the molecular level for correct clinical diagnosis.
Physical and antibiotic stresses require activation of the RsbU phosphatase to induce the general stress response in Listeria monocytogenes
Authors: Shin Ji-Hyun , Brody Margaret S. , Price Chester W.
Published: June 2010

Among pathogenic strains ofListeria monocytogenes, theσBtranscription factor has a pivotal role in the outcome of food-borne infections. This factor is activated by diverse stresses to provide general protection against multiple challenges, including those encountered during gastrointestinal passage. It also acts with the PrfA regulator to control virulence genes needed for entry into intestinal lumen cells. Environmental and nutritional signals modulateσBactivity via a network that operates by the partner switching mechanism, in which protein interactions are controlled by serine phosphorylation. This network is well characterized in the related bacteriumBacillus subtilis. A key difference inListeriais the presence of only one input phosphatase, RsbU, instead of the two found inB. subtilis. Here, we aim to determine whether this sole phosphatase is required to convey physical, antibiotic and nutritional stress signals, or if additional pathways might exist. To that end, we constructedL. monocytogenes10403S strains bearing single-copy,σB-dependentopuCA–lacZreporter fusions to determine the effects of anrsbUdeletion under physiological conditions. All stresses tested, including acid, antibiotic, cold, ethanol, heat, osmotic and nutritional challenge, required RsbU to activateσB. This was of particular significance for cold stress activation, which occurs via a phosphatase-independent mechanism inB. subtilis. We also assayed the effects of the D80N substitution in the upstream RsbT regulator that activates RsbU. The mutant had a phenotype consistent with low and uninducible phosphatase activity, but nonetheless responded to nutritional stress. We infer that RsbU activity but not its induction is required for nutritional signalling, which would enter the network downstream from RsbU.
Interaction of Rickettsia felis with histone H2B facilitates the infection of a tick cell line
Authors: Thepparit Chutima , Bourchookarn Apichai , Petchampai Natthida , Barker Steven A. , Macaluso Kevin R.
Published: June 2010

Haematophagous arthropods are the primary vectors in the transmission ofRickettsia, yet the molecular mechanisms mediating the rickettsial infection of arthropods remain elusive. This study utilized a biotinylated protein pull-down assay together with LC-MS/MS to identify interaction betweenIxodes scapularishistone H2B andRickettsia felis. Co-immunoprecipitation of histone with rickettsial cell lysate demonstrated the association of H2B withR. felisproteins, including outer-membrane protein B (OmpB), a major rickettsial adhesin molecule. The rickettsial infection of tick ISE6 cells was reduced by approximately 25 % via RNA-mediated H2B-depletion or enzymic treatment of histones. The interaction of H2B with the rickettsial adhesin OmpB suggests a role for H2B in mediatingR. felisinternalization into ISE6 cells.
Analysing the nanoporous structure of aramid fibres
Authors: Pauw Brian R. , Vigild Martin E. , Mortensen Kell , Andreasen Jens W. , Klop Enno A.
Published: June 2010

After consideration of the applicability of classical methods, a novel analysis method for the characterization of fibre void structures is presented, capable of fitting the entire anisotropic two-dimensional scattering pattern to a model of perfectly aligned, polydisperse ellipsoids. It is tested for validity against the computed scattering pattern for a simulated nanostructure, after which it is used to fit the scattering from the void structure of commercially available heat-treated poly(p-phenylene terephtalamide) fibre and its as-spun precursor fibre. The application shows a reasonable fit and results in size distributions for both the lengths and the widths of the ellipsoidal voids. Improvements to the analysis methods are compared, consisting of the introduction of an orientation distribution for the nano-ellipsoids, and the addition of large scatterers to account for the effect of fibrillar scattering on the scattering pattern. The fit to the scattering pattern of as-spun aramid fibre is improved by the introduction of the large scatterers, while the fit to the scattering pattern obtained from the heat-treated fibre improves when an orientation distribution is taken into account. It is concluded that, as a result of the heat treatment, the average width and length of the scatterers increase.
From a random to the correct structure: the VLD algorithm
Authors: Burla Maria Cristina , Giacovazzo Carmelo , Polidori Giampiero
Published: June 2010

A recent probabilistic reformulation of the difference electron-density Fourier synthesis [Burla, Caliandro, Giacovazzo & Polidori (2010).Acta Cryst.A66, 347–361] suggested that the most suitable Fourier coefficients are the sum of the classical difference term (mF−DFp) with a flipping term, depending on the model and on its quality. The flipping term is dominant when the model is poor and is negligible when the model is a good representation of the target structure. In the case of a random model the Fourier coefficient does not vanish and therefore could allow the recovery of the target structure from a random model. This paper describes a new phasing algorithm which does not require use of the concept of structure invariants or semi-invariants: it is based only on the properties of the new difference electron density and of the observed Fourier synthesis. The algorithm is cyclic and very easy to implement. It has been applied to a large set of small-molecule structures to verify the suitability of the approach.
Using thet-distribution to improve the absolute structure assignment with likelihood calculations
Authors: Hooft Rob W. W. , Straver Leo H. , Spek Anthony L.
Published: June 2010

The previously described method for absolute structure determination [Hooft, Straver & Spek (2008).J. Appl. Cryst.41, 96–103] assumes a Gaussian error distribution. The method is now extended to make it robust against poor data with large systematic errors with the introduction of the Studentt-distribution. It is shown that this modification makes very little difference for good data but dramatically improves results for data with a non-Gaussian error distribution.
The scientific impact of the Cambridge Structural Database: a citation-based study
Authors: Wong Ruth , Allen Frank H. , Willett Peter
Published: June 2010

Four groups of the most highly cited scientific articles (46 in total), which either describe the Cambridge Structural Database (CSD) System or report scientific research applications of the CSD, have been selected for citation analysis. The analysis has been carried out to study the scientific importance of crystal structure information made available to the international research communityviathe CSD orviareviews and research articles that make use of the CSD as a primary information source. Two groups,AandBof ten articles each (Apublished before 1998, andBpublished post-1998), are authored by staff of the CCDC, while two further groups,CandDcontaining ten reviews and 16 research articles, respectively, are authored by external scientific users of CSD information. Citations have been analysed by their number, and in terms of the journals, scientific subject areas and geographical regions from which the citations originate. Between them, the 46 articles have received 44 381 citations with 15 articles cited more than 1000 times. Citations come from a very broad range of journals and subject areas, with chemistry and crystallography being the dominant fields as expected, but with a very significant citation rate from the life sciences, particularly from the USA. In recent years, there has been a major increase in citations arising from south Asia and the Far East, principally from China, India, Malaysia, Pakistan, Japan, Thailand and Taiwan, who together now rival, and sometimes exceed, the citation rates from Europe and the USA. The effect of citations from new journals, particularlyActa Crystallographica Section E: Structure Reports Online,Crystal Growth and DesignandCrystEngCommis clearly reflected in the data.
X-ray measurement of residual stresses and texture development during a rolling sequence of zirconium alloy cladding tubes – influence of plastic anisotropy on mechanical behaviour
Authors: Gloaguen David , Fajoui Jamal , Girard Emmanuel , Guillén Ronald
Published: June 2010

Texture and residual stress analysis using X-ray diffraction have been carried out on zirconium alloy cladding tubes after cold pilgering, an industrial mechanical process. The final rolling pass has been completely characterized by X-ray diffraction. An interpretation of the effect of intergranular stresses on the development of analysed stress has been made using a modified elastoplastic self-consistent model in order to account for the effect of the high intrinsic plastic anisotropy of hexagonal close-packed crystals. The contribution and magnitude of the first- and second-order residual stresses were correctly evaluated using information from the model. The main features of the rolling sequence were qualitatively reproduced by the simulations, considering prismatic slip as the main active deformation mode in this alloy under large strain.
A dipicolinate lanthanide complex for solving protein structures using anomalous diffraction
Authors: Pompidor Guillaume , Maury Olivier , Vicat Jean , Kahn Richard
Published: June 2010

Tris-dipicolinate lanthanide complexes were used to prepare derivative crystals of six proteins: hen egg-white lysozyme, turkey egg-white lysozyme, thaumatin fromThaumatococcus daniellii, urate oxidase fromAspergillus flavus, porcine pancreatic elastase and xylanase fromTrichoderma reesei. Diffraction data were collected using either synchrotron radiation or X-rays from a laboratory source. In all cases, the complex turned out to be bound to the protein and the phases determined using the anomalous scattering of the lanthanide led to high-quality electron-density maps. The binding mode of the complex was characterized from the refined structures. The lanthanide tris-dipicolinate was found to bind through interactions between carboxylate groups of the dipicolinate ligands and hydrogen-bond donor groups of the protein. In each binding site, one enantiomeric form of the complex is selected from the racemic solution according to the specific site topology. For hen egg-white lysozyme and xylanase, derivative crystals obtained by cocrystallization belonged to a new monoclinicC2 crystal form that diffracted to high resolution.
Structure at 1.5 Å resolution of cytochromec552with its flexible linker segment, a membrane-anchored protein fromParacoccus denitrificans
Authors: Rajendran Chitra , Ermler Ulrich , Ludwig Bernd , Michel Hartmut
Published: June 2010

Electron transfer (ET) between the large membrane-integral redox complexes in the terminal part of the respiratory chain is mediated either by a solublec-type cytochrome, as in mitochondria, or by a membrane-anchored cytochromec, as described for the ET chain of the bacteriumParacoccus denitrificans. Here, the structure of cytochromec552fromP. denitrificanswith the linker segment that attaches the globular domain to the membrane anchor is presented. Cytochromec552including the linker segment was crystallized and its structure was determined by molecular replacement. The structural features provide functionally important information. The prediction of the flexibility of the linker region [Berry & Trumpower (1985),J. Biol. Chem.260, 2458–2467] was confirmed by our crystal structure. The N-terminal region from residues 13 to 31 is characterized by poor electron density, which is compatible with high mobility of this region. This result indicates that this region is highly flexible, which is functionally important for this protein to shuttle electrons between complexes III and IV in the respiratory chain. Zinc present in the crystallization buffer played a key role in the successful crystallization of this protein. It provided rigidity to the long negatively charged flexible loop by coordinating negatively charged residues from two different molecules and by enhancing the crystal contacts.
Isomerization mechanism of aspartate to isoaspartate implied by structures ofUstilago sphaerogenaribonuclease U2 complexed with adenosine 3′-monophosphate
Authors: Noguchi Shuji
Published: June 2010

Aspartates in proteins are isomerized non-enzymatically to isoaspartateviasuccinimidein vitroandin vivo. In order to elucidate the mechanism of isoaspartate formation within the Asp45-Glu46 sequence ofUstilago sphaerogenaribonuclease U2 based on three-dimensional structure, crystal structures of ribonuclease U2 complexed with adenosine 3′-monophosphate have been solved at 0.96 and 0.99 Å resolution. The crystal structures revealed that the Cγatom of Asp45 is located just beside the main-chain N atom of Glu46 and that the conformation which is suitable for succinimide formation is stabilized by a hydrogen-bond network mediated by water molecules 190, 219 and 220. These water molecules are suggested to promote the formation of isoaspartateviasuccinimide: in the succinimide-formation reaction water 219 receives a proton from the N atom of Glu46 as a general base and waters 190 and 220 stabilize the tetrahedral intermediate, and in the succinimide-hydrolysis reaction water 219 provides a proton for the N atom of Glu46 as a general acid. The purine-base recognition scheme of ribonuclease U2 is also discussed.
Circulating microRNA in body fluid: a new potential biomarker for cancer diagnosis and prognosis
Authors: Kosaka Nobuyoshi , Iguchi Haruhisa , Ochiya Takahiro
Published: June 2010

In the past several years, the importance of microRNA (miRNA) in cancer cells has been recognized. Proper control of miRNA expression is essential for maintaining a steady state of the cellular machinery. Recently, it was discovered that extracellular miRNAs circulate in the blood of both healthy and diseased patients, although ribonuclease is present in both plasma and serum. Most of the circulating miRNAs are included in lipid or lipoprotein complexes, such as apoptotic bodies, microvesicles, or exosomes, and are, therefore, highly stable. The existence of circulating miRNAs in the blood of cancer patients has raised the possibility that miRNAs may serve as a novel diagnostic marker. However, the secretory mechanism and biological function, as well as the meaning of the existence of extracellular miRNAs, remain largely unclear. In this review, we summarize the usefulness of circulating miRNA for cancer diagnosis, prognosis, and therapeutics. Furthermore, we propose a mechanism for the secretion and incorporation of miRNA into the cells. (Cancer Sci 2010)
Recent insights into the role of Toll-like receptors in viral infection
Authors: Carty M , Bowie A G
Published: June 2010

Toll-like receptors (TLRs) have a central role in innate immunity as they detect conserved pathogen-associated molecular patterns (PAMPs) on a range of microbes, including viruses, leading to innate immune activation and orchestration of the adaptive immune response. To date, a large number of viruses have been shown to trigger innate immunity via TLRs, suggesting that these receptors are likely to be important in the outcome to viral infection. This suggestion is supported by the observation that many viruses have evolved mechanisms not only to evade the innate immune system, but also to subvert it for the benefit of the virus. In this review we will discuss earlier evidence, mainly from knock-out mice studies, implicating TLRs in the innate immune response to viruses, in light of more recent clinical data demonstrating that TLRs are important for anti-viral immunity in humans.
Condition‐dependent, phenotype‐dependent and genetic‐dependent factors in the natal dispersal of a solitary rodent
Authors: Selonen Vesa , Hanski Ilpo K.
Published: June 2010

1. Dispersal can be condition‐ and phenotype‐dependent and related to individual genetic differences. Few studies have addressed the relative importance of these factors on dispersal. We studied the factors behind philopatry and dispersal in juvenile Siberian flying squirrels,Pteromys volansL.

2. The dispersal distance and the distances explored before abandoning the natal nest were not related to any of the condition‐dependent factors studied such as the area of high‐quality habitat or the number of conspecifics near the natal area. In addition, the body mass (a phenotypic trait) of individuals was not related to philopatry and dispersal in flying squirrels.

3. Genetic variability, measured by microsatellite heterozygosity, was positively correlated with dispersal. The correlation was mainly driven by one locus related to the distances explored before abandoning the natal nest.

4. We conclude that condition‐ and phenotype‐dependent factors did not have detectable effects on philopatry and dispersal, but individual heterozygosity was related to dispersal in flying squirrels. Our results suggest that genetic variability is important behind the dispersal of the species.
Twenty years of rest returns grazing potential, but not palatable plant diversity, to Karoo rangeland, South Africa
Authors: Seymour Colleen L. , Milton Suzanne J. , Joseph Grant S. , Dean W. Richard J. , Ditlhobolo Tsholofelo , Cumming Graeme S.
Published: June 2010

1. Up to 73% of the world’s rangelands are degraded, and increasing demand for meat in developing countries and a growing human population are likely to exert even greater pressures on rangelands in the next 20–50 years. Restoration of rangeland grazing potential and resilience is therefore important, particularly in the face of climate change.

2. We investigated the influence of past stocking rates (from 1910 to 1987), rainfall, and current grazing regimes (from 1988 to 2008) on plant assemblages, grazing potential, and diversity of palatable species in southern Karoo rangelands, South Africa.

3. We used herbivore exclusion experiments to test whether resting rangeland for 20 years enables recovery of plant assemblages (where seed sources are present within 50 m), regardless of previous grazing history. Mean annual rainfall over this period was 15% higher than the mean annual rainfall for the preceding 80 years and included two exceptionally wet years.

4. While rainfall was a primary driver of total vegetation cover, grazing history explained differences in plant species composition: plots with shared historical grazing intensity were more similar than plots with the same grazing regimes between 1988 and 2008.

5. In historically heavily‐grazed exclusion plots, cover of the palatable species Tripteris sinuata (formerly Osteospermum sinuatum) returned to levels comparable to that in both exclusion and lightly‐grazed plots with a moderate grazing history. Five palatable species (Pteronia empetrifolia, Tetragonia spicata, Berkheya spinosa, Hereroa latipetala and Ruschia spinosa) failed to re‐establish, however, despite the presence of seed‐producing plants nearby. Furthermore, only cover of P. empetrifolia increased significantly in historically moderately‐grazed plots. Cover of unpalatable plants (e.g. Pteronia pallens) increased in all plots over time.

6.
Synthesis and applications. These findings suggest that present species composition of arid shrublands reflects historical management at time scales greater than 20 years. Despite high rainfall enabling the return of grazing potential through recovery of a single forage species, rest alone did not ensure the return of all palatable species, with implications for rangeland resilience. Restoring the full suite of palatable species over management timeframes will require more complex interventions such as reseeding or selective clearing.
Limited PEG tube use: the experience of long‐term care directions
Authors: Yeh Lily , Lo Li‐Hua , Fetzer Susan , Chen Ching‐Huey
Published: June 2010

Aims and objectives.  To describe long‐term care nursing directors’ experiences with percutaneous endoscopic gastrostomy to understand the limited use of it in Taiwanese long‐term care facilities.

Background.  Percutaneous endoscopic gastrostomy tubes, used in Western countries since 1980, have not been readily used in Taiwanese long‐term care facilities since their introduction in 1995. Instead, nasogastric tubes are used for extended periods. The reasons for limited percutaneous endoscopic gastrostomy use among long‐term care residents are unknown.

Design.  A phenomenologic qualitative design using in‐depth semi‐structured interviews collected the percutaneous endoscopic gastrostomy use experiences of directors of long‐term care facilities. The directors also provided descriptive data on the prevalence of feeding tubes among their residents.

Methods.  Eight directors of long‐term care facilities in southern Taiwan participated in tape‐recorded interviews. Data were thematically analysed using the methods of Strauss and Corbin. Feeding tube prevalence data were analysed using descriptive statistics.

Results.  Four themes emerged as contributing to limited percutaneous endoscopic gastrostomy use in long‐term care facilities: acceptability, availability, affordability and accountability. Over one‐third of the residents required feeding tubes with 97% of those having nasogastric tube. Nasogastric tubes were used for a year or more in over half of the patients requiring enteral feeding.

Conclusion.  Chinese cultural values play a significant role in influencing end‐of‐life care and decisions about percutaneous endoscopic gastrostomy use. Nursing directors in long‐term care assume a gatekeeper role to promote acceptability, provide availability and ensure accountability of nutritional interventions. Policy makers must be engaged to promote the affordability of percutaneous endoscopic gastrostomy use among long‐term care residents.

Relevance to clinical practice.  To improve nutritional outcomes among long‐term care residents, nurses must acknowledge the Chinese culture related to percutaneous endoscopic gastrostomy tubes. Professionals must provide sufficient information about the advantages of percutaneous endoscopic gastrostomy tubes and discuss with families the meaning of quality of life and suffering at the end‐of‐life.
Future integrated learning environments with multimedia
Authors: Okamoto T. , Cristea A. , Kayama M.
Published: June 2010

Abstract  Recent progress in information technology hardware and the spread of the Internet have opened a variety of new ways for many fields. Although slower than the business field to catch up with these new developments, the educational field has gradually migrated towards the World‐wide web, mostly under the slogan of free, accessible education, to and from anyplace, at anytime. This development triggered an important shift from the teaching paradigm to the learning paradigm. However, slow network speed hindered the first learning environments from being more than simple, electronic text‐books. The latest trends making use of increased bandwidths and integrating various media to enhance learning. Moreover, for obtaining learner‐oriented, customised learning environ‐ments, intelligent tutoring techniques are being adapted and developed for the web. This paper presents these trends on one hand, but on the other hand, also addresses the dangers and pitfalls that such an avalanche of change can bring and stresses the task of ensuring that the real goal of enhancing and improving learning is not overlooked.
Learning through computer‐based concept mapping with scaffolding aid
Authors: Chang K.E. , Sung Y.T. , Chen S.F.
Published: June 2010

Abstract Concept mapping has been applied in a variety of fields, including instruction, learning, curriculum development, and assessment. Because many empirical studies have proven the validity of concept mapping, a computer‐based concept mapping system has been developed. The system provides two learning environments. In the ‘construct‐by‐self’ environment, the system provides students with the evaluation results and corresponding hints for feedback. The students construct concept maps by themselves with only the assistance of the feedback. In the ‘construct‐on‐scaffold’ environment, in addition to the feedback, the students receive an incomplete concept map, within which some nodes and links were set as blanks for the scaffold. A study comparing the effectiveness of the ‘construct‐by‐self’, ‘construct‐on‐scaffold’, and ‘construct by paper‐and‐pencil’ concept mapping showed that the ‘construct‐on‐scaffold’ had better effect for learning on biology. Both of the two computer‐based procedures are helpful for students in completing their concept maps.
Diazepam pharmacokinetics after nasal drop and atomized nasal administration in dogs
Authors: MUSULIN S. E. , MARIANI C. L. , PAPICH M. G.
Published: June 2010

Musulin, S. E., Mariani, C. L., Papich, M. G. Diazepam pharmacokinetics after nasal drop and atomized nasal administration in dogs.J. vet. Pharmacol. Therap.34, 17–24.

The standard of care for emergency therapy of seizures in veterinary patients is intravenous (i.v.) administration of benzodiazepines, although rectal administration of diazepam is often recommended for out‐of‐hospital situations, or when i.v. access has not been established. However, both of these routes have potential limitations. This study investigated the pharmacokinetics of diazepam following i.v., intranasal (i.n.) drop and atomized nasal administration in dogs. Six dogs were administered diazepam (0.5 mg/kg) via all three routes following a randomized block design. Plasma samples were collected and concentrations of diazepam and its active metabolites, oxazepam and desmethyldiazepam were quantified with high‐performance liquid chromatography (HPLC). Mean diazepam concentrations >300 ng/mL were reached within 5 min in both i.n. groups. Diazepam was converted into its metabolites within 5 and 10 min, respectively, after i.v. and i.n. administration. The half lives of the metabolites were longer than that of the parent drug after both routes of administration. The bioavailability of diazepam after i.n. drop and atomized nasal administration was 42% and 41%, respectively. These values exceed previously published bioavailability data for rectal administration of diazepam in dogs. This study confirms that i.n. administration of diazepam yields rapid anticonvulsant concentrations of diazepam in the dog before a hepatic first‐pass effect.
The effects of different ages and dosages on the plasma disposition and hair concentration profile of ivermectin following pour‐on administration in goats
Authors: GOKBULUT C. , CIRAK V.Y. , SENLIK B. , AKSIT D. , McKELLAR Q.A.
Published: June 2010

Gokbulut, C., Cirak, V.Y., Senlik, B., Aksit, D., McKellar, Q.A. The effects of different ages and dosages on the plasma disposition and hair concentration profile of ivermectin following pour‐on administration in goats. J. vet. Pharmacol. Therap.34, 70–75.

The effects of different ages and dosages on the plasma disposition and hair degradation of ivermectin (IVM) were investigated following pour‐on administration in goats. Twenty‐eight female Saanen goats allocated into two groups of 14 animals according to their ages as young (5–6 months old) and old (12–24 months old) groups. Each age group was divided into two further of seven goats and administered pour‐on formulation of IVM topically at the in recommended dosage rate of 0.5 mg/kg bodyweight The recommended cattle dosages rate of 0.5 mg/kg or at the higher dosage of 1.0 mg/kg. Blood samples were collected at various times between 1 h and 40 days. In addition, hair samples (>0.01 g) were collected using tweezers from the application sites and far from application sites of the all animals throughout the blood sampling period. The plasma and hair samples were analyzed by high performance liquid chromatography (HPLC) using fluorescence detection following solid and liquid phase extractions, respectively. Dose‐ and age‐dependent plasma disposition of IVM were observed in goats after pour‐on administration. In addition, relatively high concentration and slow degradation of IVM in hair samples collected from the application site and far from the application site were observed in the present study. The differences between young and old goats are probably related to differences in body condition and/or lengths of haircoat. The systemic availability of IVM following pour‐on administration is relatively much lower than after oral and subcutaneous administrations but the plasma persistence was prolonged. Although, the longer persistence of IVM on hairs on the application site may prolong of efficacy against ectoparasites, the poor plasma availability could result in subtherapeutic plasma concentrations, which may confer the risk of resistance development in for internal parasites after pour‐on administration in goats.
Reliable estimation of biochemical parameters from C3 leaf photosynthesis–intercellular carbon dioxide response curves
Authors: GU LIANHONG , PALLARDY STEPHEN G. , TU KEVIN , LAW BEVERLY E. , WULLSCHLEGER STAN D.
Published: June 2010

The Farquhar–von Caemmerer–Berry (FvCB) model of photosynthesis is a change‐point model and structurally overparameterized for interpreting the response of leaf net assimilation (A) to intercellular CO2 concentration (Ci). The use of conventional fitting methods may lead not only to incorrect parameters but also several previously unrecognized consequences. For example, the relationships between key parameters may be fixed computationally and certain fits may be produced in which the estimated parameters result in contradictory identification of the limitation states of the data. Here we describe a new approach that is better suited to the FvCB model characteristics. It consists of four main steps: (1) enumeration of all possible distributions of limitation states; (2) fitting the FvCB model to each limitation state distribution by minimizing a distribution‐wise cost function that has desirable properties for parameter estimation; (3) identification and correction of inadmissible fits; and (4) selection of the best fit from all possible limitation state distributions. The new approach implemented theoretical parameter resolvability with numerical procedures that maximally use the information content of the data. It was tested with model simulations, sampled A/Ci curves, and chlorophyll fluorescence measurements of different tree species. The new approach is accessible through the automated website leafweb.ornl.gov.
Leaf physiological responses to extreme droughts in Mediterranean Quercus ilex forest
Authors: MISSON LAURENT , LIMOUSIN JEAN‐MARC , RODRIGUEZ RAQUEL , LETTS MATTHEW G.
Published: June 2010

Global climate change is expected to result in more frequent and intense droughts in the Mediterranean region. To understand forest response to severe drought, we used a mobile rainfall shelter to examine the impact of spring and autumn rainfall exclusion on stomatal (SL) and non‐stomatal (NSL) limitations of photosynthesis in a Quercus ilex ecosystem. Spring rainfall exclusion, carried out during increasing atmospheric demand and leaf development, had a larger impact on photosynthesis than autumn exclusion, conducted at a time of mature foliage and decreasing vapour pressure deficit. The relative importance of NSL increased with drought intensity. SL and NSL were equal once total limitation (TL) reached 60%, but NSL greatly exceeded SL during severe drought, with 76% NSL partitioned equally between mesophyll conductance (MCL) and biochemical (BL) limitations when TL reached 100%. Rainfall exclusion altered the relationship between leaf water potential and photosynthesis. In response to severe mid‐summer drought stress, An and Vcmax were 75% and 72% lower in the spring exclusion plot than in the control plot at the same pre‐dawn leaf water potential. Our results revealed changes in the relationship between photosynthetic parameters and water stress that are not currently included in drought parameterizations for modelling applications.
Woody tissue photosynthesis and its contribution to trunk growth and bud development in young plants
Authors: SAVEYN AN , STEPPE KATHY , UBIERNA NEREA , DAWSON TODD E.
Published: June 2010

Stem photosynthesis can contribute significantly to woody plant carbon balance, particularly in times when leaves are absent or in ‘open’ crowns with sufficient light penetration. We explored the significance of woody tissue (stem) photosynthesis for the carbon income in three California native plant species via measurements of chlorophyll concentrations, radial stem growth, bud biomass and stable carbon isotope composition of sugars in different plant organs. Young plants of Prunus ilicifolia, Umbellularia californica and Arctostaphylos manzanita were measured and subjected to manipulations at two levels: trunk light exclusion (100 and 50%) and complete defoliation. We found that long‐term light exclusion resulted in a reduction in chlorophyll concentration and radial growth, demonstrating that trunk assimilates contributed to trunk carbon income. In addition, bud biomass was lower in covered plants compared to uncovered plants. Excluding 100% of the ambient light from trunks on defoliated plants led to an enrichment in 13C of trunk phloem sugars. We attributed this effect to a reduction in photosynthetic carbon isotope discrimination against 13C that in turn resulted in an enrichment in 13C of bud sugars. Taken together our results reveal that stem photosynthesis contributes to the total carbon income of all species including the buds in defoliated plants.