bluuebunny/crossref_metadata_2025 huggingface dataset:
Energy transfer of highly vibrationally excited naphthalene: Collisions with CHF3, CF4, and Kr
Authors: Chen Hsu Hsu , Tsai Ming-Tsang , Dyakov Yuri A. , Ni Chi-Kung
Published: August 2011

Energy transfer of highly vibrationally excited naphthalene in the triplet state in collisions with CHF3, CF4, and Kr was studied using a crossed-beam apparatus along with time-sliced velocity map ion imaging techniques. Highly vibrationally excited naphthalene (2.0 eV vibrational energy) was formed via the rapid intersystem crossing of naphthalene initially excited to the S2 state by 266 nm photons. The shapes of the collisional energy-transfer probability density functions were measured directly from the scattering results of highly vibrationally excited naphthalene. In comparison to Kr atoms, the energy transfer in collisions between CHF3 and naphthalene shows more forward scatterings, larger cross section for vibrational to translational (V → T) energy transfer, smaller cross section for translational to vibrational and rotational (T → VR) energy transfer, and more energy transferred from vibration to translation, especially in the range −ΔEd = −100 to −800 cm−1. On the other hand, the difference of energy transfer properties between collisional partners Kr and CF4 is small. The enhancement of the V → T energy transfer in collisions with CHF3 is attributed to the large attractive interaction between naphthalene and CHF3 (1–3 kcal/mol).
Colloidal rotation near the colloidal glass transition
Authors: Kim Minsu , Anthony Stephen M. , Bae Sung Chul , Granick Steve
Published: August 2011

We compare, using single-particle optical imaging, trajectories of rotation and translation for micron-sized spheres in index-matched colloidal suspensions near their glass transition. Rotational trajectories, while they show intermittent caged behavior associated with supercooled and glassy behavior, explore a sufficiently wider phase space such that in the averaged mean-square angular displacement there appears no plateau regime, but instead sub-Fickian angular diffusion that follows an apparent power law in time. We infer translation and rotation time constants, the former being the time to diffuse a particle diameter and the latter being the time to rotate a full revolution. Correlation between time constants increases with increasing volume fraction, but unlike the case for molecular glasses, the rotation time constant slows more weakly than the translation time.
How close to two dimensions does a Lennard-Jones system need to be to produce a hexatic phase?
Authors: Gribova Nadezhda , Arnold Axel , Schilling Tanja , Holm Christian
Published: August 2011

We report on a computer simulation study of a Lennard-Jones liquid confined in a narrow slit pore with tunable attractive walls. In order to investigate how freezing in this system occurs, we perform an analysis using different order parameters. Although some of the parameters indicate that the system goes through a hexatic phase, other parameters do not. This shows that to be certain whether a system of a finite particle number has a hexatic phase, one needs to study not only a large system, but also several order parameters to check all necessary properties. We find that the Binder cumulant is the most reliable one to prove the existence of a hexatic phase. We observe an intermediate hexatic phase only in a monolayer of particles confined such that the fluctuations in the positions perpendicular to the walls are less than 0.15 particle diameters, i.e., if the system is practically perfectly 2D.
Transition-metal-molecular sandwich nanowires as magnetic on/off switch
Authors: Wu Menghao , Cheng Zeng Xiao
Published: August 2011

Using first-principles calculation, we predict that upon electron injection, transition-metal-benzene [Cr(Bz)]∞ and transition-metal-ferrocene [Mn(Cp)]∞ sandwich nanowires (SWNs) can switch from nonmagnetic semiconductor to magnetic half metal. The mechanism underlying this charge-induced transition is clarified through Stoner criterion. A relationship between induced magnetic moment and injected charge density is investigated. We also find that the magnetic coupling within the [Ti(Bz)]∞ SWN can be also tuned though charge injection. Upon either hole or electron injection, the ground state of [Ti(Bz)]∞ SWN can be switched from antiferromagnetic to ferromagnetic.
Effect of low and high oil corn distillers' grain on rumen fermentation, growth performance and carcass characteristics of lambs
Authors: O'Hara A. S. , Tanner A. , McAllister T. A. , Gibb D. J. , van Herk F. , Chaves A. V.
Published: August 2011

The objective of this study was to determine the effect of replacing a mixture of canola meal and barley grain in the diet with (low and high oil) corn dried distillers’ grains with solubles (DDGS) or wheat DDGS on rumen fermentation, feed intake, growth performance and carcass traits in lambs. Seventy Canadian Arcott lambs (24.7 ± 3.21 kg) were used in a completely randomised block design over a 14-week trial. Experimental diets were provided ad libitum as pelleted total mixed rations. In the treatment diets, canola meal and barley grain were replaced with 200 g/kg of dietary DM of either high oil corn DDGS, low oil corn DDGS or wheat DDGS. A positive control diet was added to match the lipid content of 39 g/kg DM of the high oil corn DDGS diet. An in vitro rumen digestibility trial was conducted using ruminal fluid obtained from three non-lactating Holstein dairy cows. Rumen contents were also collected from each lamb at the time of slaughter for testing in vivo rumen fermentation. Data from both the in vivo and in vitro results were analysed using the MIXED procedure of SAS. The in vitro incubations revealed both corn DDGS diets produced less microbial N and microbial DM than control and wheat DDGS diets; however, this difference was too minimal to affect growth performance. Similarly, there was no dietary effect on (P > 0.05) on in vivo ruminal fermentation or carcass characteristics (P ≥ 0.19) of the lambs. Lambs fed low oil corn DDGS had lower average daily gains (P < 0.03) than those fed either high oil corn DDGS or wheat DDGS however they did not differ from those fed the control. This research demonstrated that replacing canola meal and portions of barley grain with 200 g/kg DM of either high oil corn DDGS, low oil corn DDGS or wheat DDGS in finishing lamb ratios could effectively maintain healthy rumen function, growth performance and carcass characteristics.
GPS observation of shelter utilisation by Merino ewes
Authors: Taylor D. B. , Schneider D. A. , Brown W. Y. , Price I. R. , Trotter M. G. , Lamb D. W. , Hinch G. N.
Published: August 2011

The present study examined how shelter availability, altitude and temperature influence paddock utilisation by pregnant and lambing Merino ewes. Global positioning systems (GPS) attached to collars allowed continuous tracking of ewes’ positions within two paddocks, and environmental conditions were also monitored throughout this time using temperature loggers. Animal tracking devices (UNEtracker GPS collars) were used in the spring (September–November) of 2008 (51 days) and 2009 (43 days), 14 days post-shearing, to monitor movement of pregnant grazing fine-wool Merino ewes (5 per paddock per year). The data were used to examine sheep use of lone trees, interior shelter, perimeter shelter and remainder of the paddock during three distinct diurnal activity periods, namely night camping, morning grazing and afternoon grazing. Regular use of shelter was consistently recorded in the two experimental years and in both paddocks. The ewes consistently used sheltered areas and both the leeward and windward sides of shelter, particularly during high sheep chill days. The sheep used the sheltered areas significantly more often than they used the remainder of the paddock, which was devoid of shelter except for lone trees. Night camping did not occur at the highest altitude, but predominantly where shelter was also located. The present study has demonstrated the consistent use of shelter by sheep. The shelter-seeking behaviour of the ewes a month post-shearing suggests that these animals are more sensitive to weather conditions than has been previously reported.
Mixed herb and legume pasture improves the growth of lambs post-weaning
Authors: Golding K. P. , Wilson E. D. , Kemp P. D. , Pain S. J. , Kenyon P. R. , Morris S. T. , Hutton P. G.
Published: August 2011

The potential of mixed herb and legume pastures to increase post-weaning growth rates of lambs in comparison to ryegrass-based pastures was evaluated. Unrestricted allowances of pasture treatments were offered to weaned, Romney lambs in consecutive autumns of 2007 and 2008. In Experiment 1 (2007), 300 ewe lambs were allocated for 64 days to one of four permanent sward mix treatments; chicory, plantain, red clover and white clover [herb/clover (n = 75)]; plantain, perennial ryegrass and white clover [plantain/pasture (n = 75)]; tetraploid perennial ryegrass and white clover [new pasture (n = 75)]; or diploid perennial ryegrass, other grass species and white clover [old pasture (n = 75)]. In Experiment 2 (2008), the first three pasture treatments from Experiment 1 were re-used (‘old pasture’ not used) with 168 wether lambs allocated for 35 days; herb/clover (n = 56); plantain/pasture (n = 56); and new pasture (n = 56). Unfasted liveweights of all lambs were recorded at weekly intervals and before slaughter. A sub-sample of 78 lambs from Experiment 2 was slaughtered to obtain the carcass weights, tissue depth (11 cm from the spine over the 12th rib) and commercial meat percentages. At the conclusion of Experiment 1 the herb/clover treatment lambs were heavier than the new pasture and plantain/pasture treatment lambs, which were heavier than the old pasture treatment lambs (47.4 vs 41.5 vs 41.5 vs 39.6 ± 0.4 kg, respectively) (P < 0.05). At the conclusion of Experiment 2 the herb/clover treatment lambs were heavier than the new pasture treatment lambs, which were heavier than the plantain/pasture treatment lambs (35.6 vs 32.8 vs 28.8 kg ± 0.4, respectively) (P < 0.05). In Experiment 1 a higher percent of herb/clover treatment lambs grew faster than 200 g/day (P < 0.001) than of the pasture/plantain, new pasture and old pasture treatment lambs (87 vs 4 vs 3 vs 0 percent, respectively). In Experiment 2 only the herb/clover lambs (71%) grew faster than 200 g/day (P < 0.05). In Experiment 2 herb/clover treatment lambs had heavier (P < 0.05) final carcass weight (15.7 ± 0.20 vs 14.8 ± 0.38 vs 14.6 ± 0.27 kg) compared with the plantain/pasture and new pasture lambs, respectively. It was demonstrated that a herb/clover mixed sward can increase post-weaning lamb liveweight gains during unrestricted feeding conditions compared with traditional perennial ryegrass-based pastures.
Evaluation of basic and alternative breeding programs for Sahiwal cattle genetic resources in Kenya
Authors: Ilatsia E. D. , Roessler R. , Kahi A. K. , Piepho H.-P. , Zárate A. Valle
Published: August 2011

The Sahiwal cattle breeding program in Kenya has been operational on an interim basis for over 45 years. However, there have been no systematic efforts undertaken to evaluate its suitability, or to examine how competitive it is compared with other alternative programs in terms of genetic and economic merit. The objective of this study was therefore to evaluate the genetic and economic success of the current basic and alternative Sahiwal cattle breeding programs in Kenya. The breeding programs examined were the current closed nucleus with two breeding strategies: a purebreeding (CNPURE) and a crossbreeding system (CNCROSS) involving Sahiwal sires and East African Zebu dams. An open nucleus with a certain proportion of pastoral-born Sahiwal bulls introduced into the nucleus herds to produce cows was simulated as an alternative breeding program. In this program only a purebreeding strategy (ONPURE) was considered. The breeding strategies were evaluated under two breeding objective scenarios that addressed traditional markets where animals are sold on body size/weight basis and the Kenya Meat Commission where payment is based on carcass characteristics. Sensitivity analyses to changes in nucleus size and gene contribution were also performed. The annual monetary genetic gain and profit per cow for all investigated breeding programs varied within breeding objectives. Closed nucleus purebreeding program was the most attractive economically but less competitive in regard to genetic superiority compared with either CNCROSS or ONPURE. Returns and profits were generally higher for the carcass characteristic basis compared with the body size/weight basis for all evaluated breeding strategies. Expansion of the nucleus size was not attractive because of the associated reduction in genetic and economic benefits. However, gradual importation of pastoral-born sires into the nucleus farms at the current nucleus proportion of 14% was both genetically and economically beneficial. The CNCROSS plays a complimentary role of facilitating the exploitation of trade-offs that exist between the Sahiwal and the locally better adapted East African Zebu, it also represents an intermediate phase in the on-going upgrading program.
Vascular cell-adhesion molecule-1 plays a central role in the proangiogenic effects of oxidative stress
Authors: Dong Aling , Shen Jikui , Zeng MingBing , Campochiaro Peter A.
Published: August 2011

Oxidative stress exacerbates neovascularization (NV) in many disease processes. In this study we investigated the mechanism of that effect. Mice deficient in superoxide dismutase 1 (

Sod1
−/−

mice) have increased oxidative stress and show severe ocular NV that is reduced to baseline by antioxidants. Compared with wild-type mice with ischemic retinopathy,

Sod1
−/−

mice with ischemic retinopathy had increased expression of several NF-κB–responsive genes, but expression of
vascular cell-adhesion molecule-1
(
Vcam1
) was particularly high. Intraocular injection of anti–VCAM-1 antibody eliminated the excessive ischemia-induced retinal NV. Elements that contributed to oxidative stress-induced worsening of retinal NV that were abrogated by blockade of VCAM-1 included increases in leukostasis, influx of bone marrow-derived cells, and capillary closure. Compared with ischemia alone, ischemia plus oxidative stress resulted in increased expression of several HIF-1–responsive genes caused in part by VCAM-1–induced worsening of nonperfusion and, hence, ischemia, because anti–VCAM-1 significantly reduced the increased expression of all but one of the genes. These data explain why oxidative stress worsens ischemia-induced retinal NV and may be relevant to other neovascular diseases in which oxidative stress has been implicated. The data also suggest that antagonism of VCAM-1 provides a potential therapy to combat worsening of neovascular diseases by oxidative stress.
Parallel adaptive feedback enhances reliability of the Ca
2+
signaling system
Authors: Abell Ellen , Ahrends Robert , Bandara Samuel , Park Byung Ouk , Teruel Mary N.
Published: August 2011

Despite large cell-to-cell variations in the concentrations of individual signaling proteins, cells transmit signals correctly. This phenomenon raises the question of what signaling systems do to prevent a predicted high failure rate. Here we combine quantitative modeling, RNA interference, and targeted selective reaction monitoring (SRM) mass spectrometry, and we show for the ubiquitous and fundamental calcium signaling system that cells monitor cytosolic and endoplasmic reticulum (ER) Ca
2+
levels and adjust in parallel the concentrations of the store-operated Ca
2+
influx mediator stromal interaction molecule (STIM), the plasma membrane Ca
2+
pump plasma membrane Ca–ATPase (PMCA), and the ER Ca
2+
pump sarco/ER Ca
2+
–ATPase (SERCA). Model calculations show that this combined parallel regulation in protein expression levels effectively stabilizes basal cytosolic and ER Ca
2+
levels and preserves receptor signaling. Our results demonstrate that, rather than directly controlling the relative level of signaling proteins in a forward regulation strategy, cells prevent transmission failure by sensing the state of the signaling pathway and using multiple parallel adaptive feedbacks.
Reversibility and efficiency in electrocatalytic energy conversion and lessons from enzymes
Authors: Armstrong Fraser A. , Hirst Judy
Published: August 2011

Enzymes are long established as extremely efficient catalysts. Here, we show that enzymes can also be extremely efficient
electro
catalysts (catalysts of redox reactions at electrodes). Despite being large and electronically insulating through most of their volume, some enzymes, when attached to an electrode, catalyze electrochemical reactions that are otherwise extremely sluggish (even with the best synthetic catalysts) and require a large overpotential to achieve a useful rate. These enzymes produce high electrocatalytic currents, displayed in single bidirectional voltammetric waves that switch direction (between oxidation and reduction) sharply at the equilibrium potential for the substrate redox couple. Notoriously irreversible processes such as CO
2
reduction are thereby rendered electrochemically reversible—a consequence of molecular evolution responding to stringent biological drivers for thermodynamic efficiency. Enzymes thus set high standards for the catalysts of future energy technologies.
OCT4 establishes and maintains nucleosome-depleted regions that provide additional layers of epigenetic regulation of its target genes
Authors: You Jueng Soo , Kelly Theresa K. , De Carvalho Daniel D. , Taberlay Phillippa C. , Liang Gangning , Jones Peter A.
Published: August 2011

Recent epigenome-wide mapping studies describe nucleosome-depleted regions (NDRs) at transcription start sites and enhancers. However, these static maps do not address causality or the roles of NDRs in gene control, and their relationship to transcription factors and DNA methylation is not well understood. Using a high-resolution single-molecule mapping approach to simultaneously investigate endogenous DNA methylation and nucleosome occupancies on individual DNA molecules, we show that the unmethylated OCT4 distal enhancer has an NDR, whereas NANOG has a clear NDR at its proximal promoter. These NDRs are maintained by binding of OCT4 and are required for OCT4 and NANOG expression. Differentiation causes a rapid loss of both NDRs accompanied by nucleosome occupancy, which precedes de novo DNA methylation. NDRs can be restored by forced expression of OCT4 in somatic cells but only when there is no cytosine methylation. These data show the central role of the NDRs, established by OCT4, in ensuring the autoregulatory loop of pluripotency and, furthermore, that de novo methylation follows the loss of NDRs and stabilizes the suppressed state.
L’expression de la quantité approximative en français
Authors: Giry-Schneider Jacqueline
Published: August 2011

This article deals with adjectives which, in French, are used to estimate subjectively a quantity in sentences such as Ce salaire est bas, ridicule (Those wages are low), Ce livre est épais (This book is thick), Cette pente est faible, douce (This slope is smooth). Howether, these adjective do not all have a quantitative sense as such. We therefore try to define under what syntactical and lexical conditions they can have such a quantitative meaning. Among other characteristics, they are quite unique as far as gradation is concerned. Two kinds are easily identifiable, one with adjective that can only used with nouns expressing measure, the other with adjectives that can qualify concrete objects or human beings. The latter highlights both an approximate quantity and a sensory quality. The main point was to prove that such a subjective semantical phenomenon could be described in syntactical and lexical terms.
Coexpression and activation of TRPV1 suppress the activity of the KCNQ2/3 channel
Authors: Zhang Xu-Feng , Han Ping , Neelands Torben R. , McGaraughty Steve , Honore Prisca , Surowy Carol S. , Zhang Di
Published: August 2011

Transient receptor potential vanilloid 1 (TRPV1) is a ligand-gated nonselective cation channel expressed predominantly in peripheral nociceptors. By detecting and integrating diverse noxious thermal and chemical stimuli, and as a result of its sensitization by inflammatory mediators, the TRPV1 receptor plays a key role in inflammation-induced pain. Activation of TRPV1 leads to a cascade of pro-nociceptive mechanisms, many of which still remain to be identified. Here, we report a novel effect of TRPV1 on the activity of the potassium channel KCNQ2/3, a negative regulator of neuronal excitability. Using ion influx assays, we revealed that TRPV1 activation can abolish KCNQ2/3 activity, but not vice versa, in human embryonic kidney (HEK)293 cells. Electrophysiological studies showed that coexpression of TRPV1 caused a 7.5-mV depolarizing shift in the voltage dependence of KCNQ2/3 activation compared with control expressing KCNQ2/3 alone. Furthermore, activation of TRPV1 by capsaicin led to a 54% reduction of KCNQ2/3-mediated current amplitude and attenuation of KCNQ2/3 activation. The inhibitory effect of TRPV1 appears to depend on Ca2+ influx through the activated channel followed by Ca2+-sensitive depletion of phosphatidylinositol 4,5-bisphosphate and activation of protein phosphatase calcineurin. We also identified physical interactions between TRPV1 and KCNQ2/3 coexpressed in HEK293 cells and in rat dorsal root ganglia neurons. Mutation studies established that this interaction is mediated predominantly by the membrane-spanning regions of the respective proteins and correlates with the shift of KCNQ2/3 activation. Collectively, these data reveal that TRPV1 activation may deprive neurons from inhibitory control mediated by KCNQ2/3. Such neurons may thus have a lower threshold for activation, which may indirectly facilitate TRPV1 in integrating multiple noxious signals and/or in the establishment or maintenance of chronic pain.
Motives and representability of algebraic cycles on threefolds over a field
Authors: Gorchinskiy Sergey , Guletskiĭ Vladimir
Published: August 2011

We study algebraic cycles on threefolds and finite-dimensionality of their motives with coefficients in

Q

\mathbb Q

. We decompose the motive of a non-singular projective threefold

X
X

with representable algebraic part of

C

H
0

(
X
)

CH_0(X)

into Lefschetz motives and the Picard motive of a certain abelian variety, isogenous to the Griffiths’ intermediate Jacobian

J
2

(
X
)

J^2(X)

when the ground field is

C

\mathbb C

. In particular, it implies motivic finite-dimensionality of Fano threefolds over a field. We also prove representability of zero-cycles on several classes of threefolds fibred by surfaces with algebraic

H
2

H^2

. This gives new examples of three-dimensional varieties whose motives are finite-dimensional.
A counterexample of the birational Torelli problem via Fourier–Mukai transforms
Authors: Uehara Hokuto
Published: August 2011

We study the Fourier–Mukai numbers of rational elliptic surfaces. As its application, we give an example of a pair of minimal

3
3

-folds with Kodaira dimensions

1
1

,

h
1

(

O

)
=

h
2

(

O

)
=
0

h^1(\mathcal O)=h^2(\mathcal O)=0

such that they are mutually derived equivalent, deformation equivalent, but not birationally equivalent. It also supplies a counterexample of the birational Torelli problem.
Vanishing cycle sheaves of one-parameter smoothings and quasi-semistable degenerations
Authors: Dimca Alexandru , Saito Morihiko
Published: August 2011

We study the vanishing cycles of a one-parameter smoothing of a complex analytic space and show that the weight filtration on its perverse cohomology sheaf of the highest degree is quite close to the monodromy filtration so that its graded pieces have a modified Lefschetz decomposition. We describe its primitive part using the weight filtration on the perverse cohomology sheaves of the constant sheaves. As a corollary we show in the local complete intersection case that 1 is not an eigenvalue of the monodromy on the reduced Milnor cohomology at any points if and only if the total space and the singular fiber are both rational homology manifolds. Also, we introduce quasi-semistable degenerations and calculate the limit mixed Hodge structure by constructing the weight spectral sequence. As a corollary we show non-triviality of the space of vanishing cycles of the Lefschetz pencil associated with a tensor product of any two very ample line bundles except for the case of even-dimensional projective space where two has to be replaced by three.
The Development and Estimation of a Latent Choice Multinomial Logit Model with Application to Contingent Valuation
Authors: Caudill Steven B. , Groothuis Peter A. , Whitehead John C.
Published: August 2011

We offer a new approach to investigate hypothetical bias in contingent valuation using a latent choice multinomial logit model. To develop this model, we extend Dempster, Laird, and Rubin's 1977 work on the expectations maximization algorithm to the estimation of a multinomial logit model with missing information on category membership. Our model can be used to determine within‐choice heterogeneity. Using data on the preservation of Saginaw wetlands in Michigan, we find evidence for two types of Yes responders in the data. We suggest that one set of Yes responders consists of yea‐sayers who answer Yes to the hypothetical question but are less likely to pay the bid amount if it were real. We suggest that the second group of respondents does not suffer from hypothetical bias and are more likely to pay the bid amount if it were real. Even if the connection to hypothetical bias cannot be made, our method can be used in sensitivity analyses of willingness‐to‐pay estimates.
Psychosocial Functioning and Health‐related Quality of Life in Paediatric Inflammatory Bowel Disease
Authors: Ross Sarah C. , Strachan Julie , Russell Richard K. , Wilson Sarah L.
Published: August 2011

Objectives:

The present systematic review examined the literature focusing on psychosocial functioning and health‐related quality of life (HRQOL) in young people with inflammatory bowel disease (IBD). It aimed to critique the methodological quality of the identified studies, discuss the implications of their findings, and make recommendations for future research.

Patients and Methods:

Relevant articles (January 1990–December 2009) were subject to strict inclusion and exclusion criteria. Identified papers were rated for methodological quality using SIGN 50 and Critical Appraisal Skills Programme guidelines before data extraction.

Results:

Of 2141 articles initially identified, 278 were screened in detail, leaving 12 articles for inclusion in the review: 3 having “acceptable” and 9 having “good” quality rating scores. These 12 studies yielded a combined total of 5330 participants including 790 with IBD and 4540 controls (ages 4–18 years). Five main outcomes—self‐esteem, HRQOL, anxiety and depression, social competence, and behavioural functioning—were examined. Three of the 4 controlled studies addressing self‐reported HRQOL found it to be significantly lower in the participants with IBD. The evidence for lowered self‐esteem, self‐reported symptoms of depression and anxiety, impaired social competence, and behavioural problems were conflicting. Methodological heterogeneity was noted in terms of areas of functioning addressed, measures used, sample size, and use of control groups.

Conclusions:

HRQOL is lower in patients with IBD, but conflicting results and methodological flaws limit conclusions on other aspects of psychosocial functioning. Future research should present data on effect sizes, avoid confounding findings by not combining across age groups or disease severity indices, and consider investigating body image disturbance.
Secretory nucleoside diphosphate kinases from both intra- and extracellular pathogenic bacteria are functionally indistinguishable
Authors: Dar Haider Hussain , Prasad Deepshikha , Varshney Grish C. , Chakraborti Pradip K.
Published: August 2011

Nucleoside diphosphate kinase (NDK), responsible for the maintenance of NTP pools, is an ATP-utilizing enzyme secreted by different pathogens. We found that NDK fromSalmonella entericaserovar Typhimurium (S.Typhimurium) is also secretory in nature. Secretory NDK is known to play a crucial role in the survival of pathogenic microbes within host cells through their interaction with extracellular ATP. To elucidate this aspect, we assessed the contribution of secretory products containing NDK from intracellular (Mycobacterium tuberculosisandS.Typhimurium) and extracellular (Vibrio cholerae) pathogens to the process of ATP-induced J774 mouse macrophage cell lysis by monitoring lactate dehydrogenase (LDH) release in the culture medium. Compared with an untreated control, our results demonstrate thatS.Typhimurium secretory products caused a greater than twofold decrease in LDH release from J774 macrophage cells treated with ATP. Furthermore, the secretory products from anndk-deleted strain ofS.Typhimurium did not display such behaviour. Contrary to this observation, the secretory products containing NDK ofV. choleraewere found to be cytotoxic to J774 cells. At the amino acid level, the sequences of both the NDKs (S.Typhimurium andV. cholerae) exhibited 65 % identity, and their biochemical characteristics (autophosphorylation and phosphotransfer activities) were indistinguishable. However, to our surprise, the secretory product of anndk-deleted strain ofS.Typhimurium, when complemented withV. cholerae ndk, was able to prevent ATP-induced cytolysis. Taken together, our results unambiguously imply that the intrinsic properties of secretory NDKs are identical in intra- and extracellular pathogens, irrespective of their mode of manifestation.
Quantitative RNA-seq analysis of the Campylobacter jejuni transcriptome
Authors: Chaudhuri Roy R. , Yu Lu , Kanji Alpa , Perkins Timothy T. , Gardner Paul P. , Choudhary Jyoti , Maskell Duncan J. , Grant Andrew J.
Published: August 2011

C
ampylobacter jejuni is the most common bacterial cause of foodborne disease in the developed world. Its general physiology and biochemistry, as well as the mechanisms enabling it to colonize and cause disease in various hosts, are not well understood, and new approaches are required to understand its basic biology. High-throughput sequencing technologies provide unprecedented opportunities for functional genomic research. Recent studies have shown that direct Illumina sequencing of cDNA (RNA-seq) is a useful technique for the quantitative and qualitative examination of transcriptomes. In this study we report RNA-seq analyses of the transcriptomes of C. jejuni (NCTC11168) and its rpoN mutant. This has allowed the identification of hitherto unknown transcriptional units, and further defines the regulon that is dependent on rpoN for expression. The analysis of the NCTC11168 transcriptome was supplemented by additional proteomic analysis using liquid chromatography-MS. The transcriptomic and proteomic datasets represent an important resource for the Campylobacter research community.
Everybody’s Business? A Research Review of the Informal Safeguarding of Other People’s Children in the UK
Authors: Holland Sally , Tannock Stuart , Collicott Hayley
Published: August 2011

The paper reviews public discourses and research on the safeguarding of other people’s children by adults at the neighbourhood level. There is much empirical evidence pointing to the existence of thriving informal communities of support and informal childcare for parents across the social classes. There appears to be less empirical evidence related to intervening with children and young people who may be at risk. Nonetheless, the limited evidence suggests that many neighbours, acquaintances and strangers do intervene, or say that they would. The paper concludes by considering the potential negative consequences of promoting the notion that safeguarding children is ‘everybody’s business’.
Correlation of mutant menin stability with clinical expression of multiple endocrine neoplasia type 1 and its incomplete forms
Authors: Shimazu Satoko , Nagamura Yuko , Yaguchi Hiroko , Ohkura Naganari , Tsukada Toshihiko
Published: August 2011

Germline mutations of the tumor suppressor gene MEN1 are found not only in typical multiple endocrine neoplasia type 1 (MEN1) but also in its incomplete forms such as familial isolated hyperparathyroidism (FIHP) and apparently sporadic parathyroid tumor (ASPT). No definitive genotype–phenotype correlation has been established between these clinical forms and MEN1 gene mutations. We previously demonstrated that mutant menin proteins associated with MEN1 are rapidly degraded by the ubiquitin–proteasome pathway. To examine whether the intracellular stability of mutant menin is correlated with clinical phenotypes, we developed a method of evaluating menin stability and examined 20 mutants associated with typical MEN1 (17 missense, two in‐frame deletion, one nonsense) and 21 mutants associated with FIHP or ASPT (19 missense, two in‐frame deletion). All tested mutants associated with typical MEN1 showed reduced stability. Some missense and in‐frame deletion mutants (G28A, R171W, T197I, E255K, E274A, Y353del and E366D) associated with FIHP or ASPT were almost as stable as or only slightly less stable than wild‐type menin, while others were as unstable as those associated with typical MEN1. Some stable mutants exhibited substantial biological activities when tested by JunD‐dependent transactivation assay. These findings suggest that certain missense and in‐frame mutations are fairly stable and retain intrinsic biological activity, and might be specifically associated with incomplete clinical phenotypes. The menin stability test will provide useful information for the management of patients carrying germline MEN1 mutations especially when they have missense or in‐frame variants of ambiguous clinical significance. (Cancer Sci 2011; 102: 2097–2102)
Expression of genes from the lignin synthesis pathway in guineagrass genotypes differing in cell‐wall digestibility
Authors: Stabile S. S. , Bodini A. P. , Jank L. , Rennó F. P. , Santos M. V. , Silva L. F. P.
Published: August 2011

Rapid decline in cell‐wall digestibility hinders efficient use of warm‐season grasses. The objective of this study was to identify genes whose expressions are related to the slope of decline in cell‐wall digestibility. Eleven guineagrass genotypes were harvested at three ages and classified according to fibre digestibility. Extreme genotypes were separated into groups with either FAST or SLOW decline in fibre digestibility. Expression of transcripts from six genes from the lignin synthesis pathway was quantified by real‐time PCR. Fast decline in fibre digestibility was associated with higher DM yield after 90 d of regrowth. Apart from lower fibre digestibility and higher lignin content for the FAST group, there were no other differences between the two groups for the chemical composition of stems and leaves. Maturity affected differently the expression of two of the six genes, cinnamate 4‐hydroxylase and caffeoyl‐CoA O‐methyltransferase (C4H and CCoAOMT). Genotypes with fast decline in fibre digestibility had greater increase in the expression of C4H and CCoAOMT from 30 to 60 d of regrowth, than genotypes with slower decline. Expression of C4H and CCoAOMT appears to be related to the decline in cell‐wall digestibility with advance in maturity of guineagrass.
Virtuous acts as practical medical ethics: an empirical study
Authors: Little Miles , Gordon Jill , Markham Pippa , Rychetnik Lucie , Kerridge Ian
Published: August 2011

Rationale, aims and objectives To examine the nature, scope and significance of virtues in the biographies of medical practitioners and to determine what kind of virtues are at play in their ethical behaviour and reflection.

Methods A case study involving 19 medical practitioners associated with the Sydney Medical School, using semi‐structured narrative interviews. Narrative data were analysed using dialectical empiricism, constant comparison and iterative reformulation of research questions.

Results Participants represented virtuous acts as centrally important in their moral assessments of both themselves and others. Acts appeared to be contextually virtuous, rather than expressions of stable character traits, and virtue was linked to acts that served to protect or enhance fundamental values attached to ontological security and human flourishing. Virtue ethics, in this sense, was the single most important ethical system for each of the participants.

Conclusion Virtue ethics, construed as the appraisal of acts in contexts of risk, danger or threat to foundational values, emerged as the ‘natural’ ethical approach for medical practitioners in this case study. Teaching medical ethics to students and graduates alike needs to accommodate the priority attached to virtuous acts.
Transcription factor genes of Schizophyllum commune involved in regulation of mushroom formation
Authors: Ohm Robin A. , de Jong Jan F. , de Bekker Charissa , Wösten Han A. B. , Lugones Luis G.
Published: August 2011

Mushrooms represent the most conspicuous structures of fungi. Their development is being studied in the model basidiomycete Schizophyllum commune. The genome of S. commune contains 472 genes encoding predicted transcription factors. Of these, fst3 and fst4 were shown to inhibit and induce mushroom development respectively. Here, we inactivated five additional transcription factor genes. This resulted in absence of mushroom development (in the case of deletion of bri1 and hom2), in arrested development at the stage of aggregate formation (in the case of c2h2) and in the formation of more but smaller mushrooms (in the case of hom1 and gat1). Moreover, strains in which hom2 and bri1 were inactivated formed symmetrical colonies instead of irregular colonies like the wild type. A genome‐wide expression analysis identified several gene classes that were differentially expressed in the strains in which either hom2 or fst4 was inactivated. Among the genes that were downregulated in these strains were c2h2 and hom1. Based on these results, a regulatory model of mushroom development in S. commune is proposed. This model most likely also applies to other mushroom‐forming fungi and will serve as a basis to understand mushroom formation in nature and to enable and improve commercial mushroom production.
Combined experimental and computational strategies define an expansive regulon for GcvB small RNA
Authors: Vanderpool Carin K.
Published: August 2011

The bacterial small RNA GcvB has been known as a translational repressor of mRNAs encoding amino acid transporters and has been postulated to limit uptake of unnecessary amino acids under nutrient‐rich conditions. In this issue of Molecular Microbiology, Sharma et al. (2011) provide evidence for a much broader role for GcvB as a global regulator of amino acid metabolism. Using a unique combination of experimental and biocomputational approaches, the authors triple the size of the GcvB regulon, making it the largest sRNA regulon defined to date.
A seven‐WD40 protein related to human RACK1 regulates mating and virulence in Ustilago maydis
Authors: Wang Lei , Berndt Patrick , Xia Xiaojuan , Kahnt Jörg , Kahmann Regine
Published: August 2011

In mammalian cells RACK1 serves as a scaffold protein that has a role in integrating inputs from different signalling pathways and affects translation through association with ribosomes. Ustilago maydis contains a seven‐WD40 repeat motif protein designated Rak1, which shows 68% identity to RACK1 and 51% identity to Asc1p of Saccharomyces cerevisiae. An asc1 mutant could be complemented by introduction of U. maydis rak1. The deletion of rak1 affected cell growth, cell wall integrity and specifically attenuated cell fusion. This latter defect was caused by reduced expression of prf1 encoding the regulator for pheromone (mfa) and pheromone‐receptor genes. Rak1 interacts with a variety of ribosomal proteins and microarray analysis revealed that the deletion of rak1 led to severely reduced expression of rop1, a transcriptional activator of prf1. The constitutive expression of rop1 could rescue the defect of mfa1 expression as well as conjugation tube formation in response to pheromone induction in the rak1 mutant. Moreover, a solopathogenic rak1 mutant failed to respond to plant‐derived stimuli, resulting in attenuated filamentation and pathogenicity. This could be partially rescued by constitutive expression of the b heterodimer. These data suggest that rak1 is a regulator of rop1 expression with additional roles after cell fusion.
Leafcutter ants: a small dispersal agent of the invasive plant Murraya paniculata
Authors: PIKART T G , SOUZA G K , SERRÃO J E , ZANUNCIO J C
Published: August 2011

Pikart TG, Souza GK, Serrão JE & Zanuncio JC (2011). Leafcutter ants: a small dispersal agent of the invasive plant Murraya paniculata. Weed Research51, 548–551.

Ants can play an important role in the success and impact of many species invasions, including weed species. This study, in a fragment of secondary forest in Viçosa, Minas Gerais State, Brazil, evaluates the role of native leafcutter ants in the spread of the exotic plant Murraya paniculata, an alternative host of bacteria causing citrus greening disease. The foraging activity of leafcutter ants on fruits of ten M. paniculata plants was observed daily during August 2010. The only leafcutter ant species observed was Acromyrmex niger (Smith, 1858) (Hymenoptera: Formicidae), which showed a preference to remove M. paniculata fruits to its nests, cleaning them and discarding the seeds on refuse piles afterwards. Murraya paniculata was the main plant whose seeds were deposited in refuse piles (61–82% of the seeds), where they commonly germinated. This study shows that dispersal of this weed is facilitated by native leafcutter ants. This may promote the spread and establishment of this alternative host of citrus greening disease and so lead to problems in monitoring and control of this disease.
Does predation result in adult sex ratio skew in a sexually dimorphic insect genus?
Authors: WEHI P. M. , NAKAGAWA S. , TREWICK S. A. , MORGAN‐RICHARDS M.
Published: August 2011

Theory proposes that sexually dimorphic, polygynous species are at particularly high risk of sex‐biased predation, because conspicuous males are more often preyed upon compared to females. We tested the effects of predation on population sex ratio in a highly sexually dimorphic insect genus (Hemideina). In addition, introduction of a suite of novel mammalian predators to New Zealand during the last 800 years is likely to have modified selection pressures on native tree weta. We predicted that the balance between natural and sexual selection would be disrupted by the new predator species. We expected to see a sex ratio skew resulting from higher mortality in males with expensive secondary sexual weaponry; combat occurs outside refuge cavities between male tree weta. We took a meta‐analytic approach using generalized linear mixed models to compare sex ratio variation in 58 populations for six of the seven species in Hemideina. We investigated adult sex ratio across these populations to determine how much variation in sex ratio can be attributed to sex‐biased predation in populations with either low or high number of invasive mammalian predators. Surprisingly, we did not detect any significant deviation from 1 : 1 parity for adult sex ratio and found little difference between populations or species. We conclude that there is little evidence of sex‐biased predation by either native or mammalian predators and observed sex ratio skew in individual populations of tree weta is probably an artefact of sampling error. We argue that sex‐biased predation may be less prevalent in sexually dimorphic species than previously suspected and emphasize the usefulness of a meta‐analytic approach to robustly analyse disparate and heterogeneous data.
Impact of different inclusion levels of oil palm (Elaeis guineensis Jacq.) fronds on fatty acid profiles of goat muscles
Authors: Ebrahimi M. , Rajion M. A. , Goh Y. M. , Sazili A. Q.
Published: August 2011

The effects of different inclusion levels of oil palm fronds (OPF) on the fatty acid profile of the longissimus dorsi (LD), biceps femoris (BF) and infraspinatus (IS) muscle of goats fed for 100 days are described. Twenty‐four individually housed Kacang crossbred male goats (averaged 21.7 ± 0.97 kg BW) were allocated to three groups receiving either a 100% concentrate control diet (CON), diet with 25% inclusion level of OPF (HAF) or a diet with 50% inclusion of OPF. The diets were adjusted to be isocaloric and isonitrogenous and fed at 3.0% of BW daily. Samples of LD, BF and IS muscles were taken at slaughter for the determination of fatty acid profiles. The total saturated fatty acids (SFA) in the LD and BF muscles of the OPF group were significantly (p < 0.05) lower than the CON group. For all muscles, C18:3n‐3 and total n‐3 polyunsaturated fatty acid (PUFA) were significantly higher (p < 0.05) in the OPF group than the CON group with minimal impact on the C18:2n‐6 and total n‐6PUFA. Consequently, the n‐6:n‐3 ratio significantly (p < 0.05) decreased in the OPF group compared to the CON group. The LD muscle had a significantly higher conjugated linoleic acid 18:2 c19t11 compared to other muscles. There were no interactions between muscle x diet except for total SFA. It is concluded that OPF at 25–50% inclusion levels may decrease the SFA and increase the n‐3PUFA content in chevon, with no apparent adverse effects on the growth performance of the animals, can be used as a feed ingredient to support goat farming in countries that lack grazing pasture.
Academic Stratification and the Sustaining of Identity Types
Authors: Maddock John
Published: August 2011

‘We have nothing against them but we don't mingle much with them. Classes seem to be divided into intelligence levels. Brains hang around with brains. People with average intelligence hang around with people of average intelligence.’

Stream One (two languages, including Latin) girl.
Relations between Strangers: Cycles of Structure and Meaning in Tourist Systems
Authors: Machlis Gary E. , Burch William R.
Published: August 2011

Tourism is a paradoxical human activity—a supposedly ‘smokeless industry’ that produces littered beaches, a cornucopia to local economics that gives rise to inflation and embittered natives, a profitable enterprise that often requires governmental subsidy. It is also a major social and economic phenomenon: witness 280 million international tourists and 180 billion dollars in expenditures in 1979 (Waters, 1979). For the populations of many societies, it is a primary source of work; for others it is a primary outlet for leisure. An understanding of the modern era is incomplete without understanding the social processes of tourism.

This paper speculates about cycles of structure and myth in tourism development. The goal is an integrated theory of tourism, based on empirical evidence, amenable to test, and permitting the prediction of future behaviour.

The paper is divided into several sections. First, we briefly review some earlier analytic frameworks used for understanding tourism. We draw upon these frameworks to develop an integrated explanation of the behaviour of tourists, the evolution of the tourist industry, and the consequences of tourism for host and guest populations. Second, our attention is devoted to structural and symbolic factors shaping relations between strangers. Such relations, we argue, are the engine of change in tourism. Third, we present a typology of the social cycles involved in tourism. We attempt to describe which elements of the social order are likely to respond in predictable patterns to tourism development; speculate on the form these responses might take and provide a set of hypothetical curves for potential indicator measures. We close by suggesting some theoretical and practical implications of our discussion.