bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of high-k TiOx dielectric on device performance of indium-gallium-zinc oxide transistors
Authors: Park Jin-Seong , Jeong Jae Kyeong , Mo Yeon-Gon , Kim Sangwook
Published: January 2009

We investigated the effect of the high-k TiOx (k∼40) gate dielectric on the mobility (μFE) of indium-gallium-zinc oxide (IGZO) transistors. As the thickness of the TiOx layer at the interface of the IGZO channel and SiNx gate dielectric layer increased from 2 to 8 nm, the μFE value was monotonously reduced from 9.9 to 1.8 cm2/V s. The degradation of the mobility was attributed to the Coulomb scattering mechanism rather than the phonon scattering mechanism of the high-k TiOx layer based on the behavior of the temperature-dependent mobilities for all of the IGZO transistors.
Surface morphology and magnetic anisotropy of Fe/MgO(001) films deposited at oblique incidence
Authors: Zhan Qing-feng , Van Haesendonck Chris , Vandezande Stijn , Temst Kristiaan
Published: January 2009

We studied surface morphology and magnetic properties of Fe/MgO(001) films deposited at an angle varying between 0° and 60° with respect to the surface normal and with azimuth along the Fe[010] or the Fe[110] direction. Due to shadowing, elongated grains appear on the film surface for deposition at sufficiently large angle. X-ray reflectivity reveals that, depending on the azimuthal direction, films become either rougher or smoother for oblique deposition. For deposition along Fe[010] the pronounced uniaxial magnetic anisotropy (UMA) results in the occurrence of “reversed” two-step and of three-step hysteresis loops. For deposition along Fe[110] the growth-induced UMA is much weaker, causing a small rotation of the easy axes.
Perceptions and Experience of Employment Regulation in UK Small Firms
Authors: Carter Sara , Mason Colin , Tagg Stephen
Published: January 2009

The view that excessive regulation constrains small business growth has been a persistent theme within business and policy communities, although recent studies have demonstrated the actual effects of regulation to be relatively modest. A prior small-scale study proposed four reasons why employment legislation does “not damage” small firms. We attempt to assess the robustness of these propositions in a large-scale survey of 16 779 small firms. Results provide empirical support for three propositions. Firstly, perceived dissatisfaction masks actual effects. Secondly, competitive conditions mediate regulatory effects; however, even resource-constrained firms reported few negative effects. Thirdly, informality eases regulatory impact. Results failed to confirm that older laws are ‘routinised’. Length of time as a business owner was found to be more influential than age of regulation, with owners who have been in business for many years having a longer ‘window of exposure’ increasing their likelihood of experiencing negative and positive effects.
Discouraged Advisees? The Influence of Gender, Ethnicity, and Education in the Use of Advice and Finance by UK SMEs
Authors: Scott Jonathan M , Irwin David
Published: January 2009

We investigate the influence of gender, ethnicity, and education in the use of external advice and finance by UK small and medium-sized enterprises (SMEs). A conceptual model of ‘discouraged advisees’ was developed as a framework for analysis of the results of a telephone survey of 400 SMEs. We found an association between the use of external advice and the ability to raise bank finance. Furthermore, both men and black and minority ethnic (BME) participants were more likely to use family and friends for advice, whilst women were twice as likely as men to use Business Link. BME business owners were discouraged from using less ‘trusted’ sources, such as Business Link, possibly believing them insufficiently tailored or that they would provide inappropriate advice. Therefore, the findings provide support for our conceptual model of discouraged advisees and have implications for the provision of advice for business owners from BME communities.
The Politics of Sustainable Development in UK Government: What Role for Integrated Policy Appraisal?
Authors: Russel Duncan , Turnpenny John
Published: January 2009

Attempts to better integrate policy in pursuit of more sustainable development have been made by many countries through the application of ex ante policy appraisal to sectoral policies. The United Kingdom (UK) is often cited as an international leader in this regard, but this is by no means clear. We examine empirically the extent to which the UK Regulatory Impact Assessment (RIA) system facilitates more integrated, and ultimately sustainable, policies. It appears RIA practice is far from integrated. Many RIAs cover a narrow range of impacts, are conducted late in the policy process, have relatively closed consultation processes, do not explicitly show how trade-offs were made, and use analysis inconsistently, if at all. We argue that providing more resources and improving quality control for RIA may improve integration to only a limited degree. More fundamental barriers to integration are hindered by closed policy communities and institutional processes and therefore may be more difficult to overcome.
Entrepreneurship Policies and New Business Performance and Growth: An Empirical Analysis Based on Manufacturing Industries
Authors: Martínez José A Belso
Published: January 2009

Entrepreneurship policy is an emerging area among economic policy developments that is currently not well developed. Policy makers are seeking to increase countries' and regions' entrepreneurial vitality in recognition of the growing evidence that a high level of entrepreneurial activity contributes to economic growth and development. I report the results of a cross-sectional empirical analysis that was conducted to test the contribution of different types of entrepreneurship development programs to new business performance and growth. A sample of seventy-two Spanish footwear entrepreneurs were contacted and surveyed during 2000. Major findings suggest that some of the analyzed public policies significantly favor new business profitability and growth. These results should be taken with care because of the sample size, the profile of the economic sector analyzed, and the restricted geographical location of the new businesses considered in this research.
Reproductive physiology of the female greater bilby (Macrotis lagotis Thylacomyidae): evidence for a male-induced luteal phase
Authors: Ballantyne K. , Matson P. , Noakes N. , Nicolson V. , Johnston S. D.
Published: January 2009

Endocrinology of the oestrous cycle, pregnancy and early lactation was investigated in captive Western Australian greater bilbies (Macrotis lagotis). Initially, six females were monitored for changes in urogenital cytology, plasma progestogen, pericloacal and pouch morphology in the absence of a male. This was followed by the introduction of a male and a reproductive assessment through mating, gestation and early lactation. In the absence of a male, there was no cyclical pattern of urogenital cytology, pericloacal or pouch development, and progestogen concentrations remained basal. Within 5 days of the introduction of a male, all females had a karyopycnotic index of 100%. Spermatozoa were present in the urogenital smear within 3 days of male introduction in all five females that gave birth. Five to 9 days after the introduction of a male, there was an increase in plasma progestogen concentration that remained elevated for 14–19 days. Six of the seven females gave birth approximately 3 days after reaching peak plasma progestogen concentrations. Gestation length ranged between 14 and 17 days. Plasma progestogen concentrations of the postpartum and early lactation period were lower (P < 0.0001) than during gestation, but greater (P < 0.0001) than those recorded before the introduction of a male. One female that gave birth early in the study that was examined until weaning of the pouch young showed a cyclical pattern of plasma progestogen secretion that ended at weaning. This study provides evidence that the luteal phase in the greater bilby is induced by the presence of a male. Similar to female reproductive physiology in the Peramelidae, elevated progestogen concentration in the greater bilby was extended into lactation.
Abnormal changes in mitochondria, lipid droplets, ATP and glutathione content, and Ca2+ release after electro-activation contribute to poor developmental competence of porcine oocyte during in vitro ageing
Authors: Hao Ze-Dong , Liu Shen , Wu Yi , Wan Peng-Cheng , Cui Mao-Sheng , Chen Heng , Zeng Shen-Ming
Published: January 2009

The present study aims to investigate major changes in porcine oocytes during ageing in vitro. After the oocytes were cultured for 44, 56, 68 and 80 h, changes to porcine oocytes in ultrastructure, mitochondrial distribution, glutathione (GSH) and ATP content, Ca2+ release patterns and developmental competence after electro-activation were observed. Mitochondria were evenly distributed in oocytes at 44 h, aggregated in clusters or in peripheral cytoplasm at 68 h and dimly dispersed throughout ooplasm at 80 h. Mitochondrial shape during ageing was also observed by transmission electron microscopy (TEM) at the same time intervals. Most mitochondria were spherical at 44 h, and became elongated when the culture time was extended to 68 h and 80 h. Moreover, mitochondrial clustering became increasingly loose from 56 h. Lipid droplets in oocytes appeared prominent and electron-dense at 44 h, but electron density was lost at 56 h. Lipid droplets were solidified as of 68 h. There was an age-dependent decrease in ATP content per oocyte. Glutathione content per oocyte decreased significantly and remained lower after 56 h. Amplitudes of [Ca2+] rise decreased dramatically following 56 h, and the time required for [Ca2+] to plateau became shorter after electro-activation with prolonged culture time. Cleavage and blastocyst rates of aged oocytes progressively decreased, while the fragmentation rate gradually increased after electro-activation. It is concluded that abnormal changes in mitochondria, lipid droplets, Ca2+ release after electro-activation, and ATP and GSH content in oocytes during ageing may result in poor developmental competence of parthenotes.
R-Spondin1 protects mice from chemotherapy or radiation-induced oral mucositis through the canonical Wnt/β-catenin pathway
Authors: Zhao Jingsong , Kim Kyung-Ah , De Vera Josephine , Palencia Servando , Wagle Marie , Abo Arie
Published: January 2009

R-Spondin1 (RSpo1) is a novel secreted protein that augments canonical Wnt/β-catenin signaling. We injected recombinant RSpo1 protein into transgenic Wnt reporter TOPGAL mice and have identified the oral mucosa as a target tissue for RSpo1. Administration of RSpo1 into normal mice triggered nuclear translocation of β-catenin and resulted in increased basal layer cellularity, thickened mucosa, and elevated epithelial cell proliferation in tongue. We herein evaluated the therapeutic potential of RSpo1 in treating chemotherapy or radiotherapy-induced oral mucositis in several mouse models. Prophylactic treatment with RSpo1 dose-dependently overcame the reduction of basal layer epithelial cellularity, mucosal thickness, and epithelial cell proliferation in tongues of mice exposed to whole-body irradiation. RSpo1 administration also substantially alleviated tongue mucositis in the oral cavity of mice receiving concomitant 5-fluorouracil and x-ray radiation. Furthermore, RSpo1 significantly reduced the extent of tongue ulceration in mice receiving a single fraction, high dose head-only radiation in a dose-dependent manner. Moreover, combined therapy of RSpo1 and keratinocyte growth factor resulted in complete healing of tongue ulcers in mice subjected to snout-only irradiation. In conclusion, our results demonstrate RSpo1 to be a potent therapeutic agent for oral mucositis by enhancing basal layer epithelial regeneration and accelerating mucosal repair through up-regulation of Wnt/β-catenin pathway.
C-type lectin Mincle is an activating receptor for pathogenic fungus,Malassezia
Authors: Yamasaki Sho , Matsumoto Makoto , Takeuchi Osamu , Matsuzawa Tetsuhiro , Ishikawa Eri , Sakuma Machie , Tateno Hiroaki , Uno Jun , Hirabayashi Jun , Mikami Yuzuru , Takeda Kiyoshi , Akira Shizuo , Saito Takashi
Published: January 2009

Mincle (also called as Clec4e and Clecsf9) is a C-type lectin receptor expressed in activated phagocytes. Recently, we have demonstrated that Mincle is an FcRγ-associated activating receptor that senses damaged cells. To search an exogenous ligand(s), we screened pathogenic fungi using cell line expressing Mincle, FcRγ, and NFAT-GFP reporter. We found that Mincle specifically recognizes theMalasseziaspecies among 50 different fungal species tested.Malasseziais a pathogenic fungus that causes skin diseases, such as tinea versicolor and atopic dermatitis, and fatal sepsis. However, the specific receptor on host cells has not been identified. Mutation of the putative mannose-binding motif within C-type lectin domain of Mincle abrogatedMalasseziarecognition. Analyses of glycoconjugate microarray revealed that Mincle selectively binds to α-mannose but not mannan. Thus, Mincle may recognize specific geometry of α-mannosyl residues onMalasseziaspecies and use this to distinguish them from other fungi.Malasseziaactivated macrophages to produce inflammatory cytokines/chemokines. To elucidate the physiological function of Mincle, Mincle-deficient mice were established.Malassezia-induced cytokine/chemokine production by macrophages from Mincle−/−mice was significantly impaired. In vivo inflammatory responses againstMalasseziawas also impaired in Mincle−/−mice. These results indicate that Mincle is the first specific receptor forMalasseziaspecies to be reported and plays a crucial role in immune responses to this fungus.
A hybrid nanomemristor/transistor logic circuit capable of self-programming
Authors: Borghetti Julien , Li Zhiyong , Straznicky Joseph , Li Xuema , Ohlberg Douglas A. A. , Wu Wei , Stewart Duncan R. , Williams R. Stanley
Published: January 2009

Memristor crossbars were fabricated at 40 nm half-pitch, using nanoimprint lithography on the same substrate with Si metal-oxide-semiconductor field effect transistor (MOS FET) arrays to form fully integrated hybrid memory resistor (memristor)/transistor circuits. The digitally configured memristor crossbars were used to perform logic functions, to serve as a routing fabric for interconnecting the FETs and as the target for storing information. As an illustrative demonstration, the compound Boolean logic operation (A AND B) OR (C AND D) was performed with kilohertz frequency inputs, using resistor-based logic in a memristor crossbar with FET inverter/amplifier outputs. By routing the output signal of a logic operation back onto a target memristor inside the array, the crossbar was conditionally configured by setting the state of a nonvolatile switch. Such conditional programming illuminates the way for a variety of self-programmed logic arrays, and for electronic synaptic computing.
Model of genetic variation in human social networks
Authors: Fowler James H. , Dawes Christopher T. , Christakis Nicholas A.
Published: January 2009

Social networks exhibit strikingly systematic patterns across a wide range of human contexts. Although genetic variation accounts for a significant portion of the variation in many complex social behaviors, the heritability of egocentric social network attributes is unknown. Here, we show that 3 of these attributes (in-degree, transitivity, and centrality) are heritable. We then develop a “mirror network” method to test extant network models and show that none account for observed genetic variation in human social networks. We propose an alternative “Attract and Introduce” model with two simple forms of heterogeneity that generates significant heritability and other important network features. We show that the model is well suited to real social networks in humans. These results suggest that natural selection may have played a role in the evolution of social networks. They also suggest that modeling intrinsic variation in network attributes may be important for understanding the way genes affect human behaviors and the way these behaviors spread from person to person.
The Src family kinase, Lyn, suppresses osteoclastogenesis in vitro and in vivo
Authors: Kim Hyun-Ju , Zhang Kaihua , Zhang Lihong , Ross F. Patrick , Teitelbaum Steven L. , Faccio Roberta
Published: January 2009

c-Src kinase is a rate-limiting activator of osteoclast (OC) function and Src inhibitors are therefore candidate antiosteoporosis drugs. By affecting αvβ3 and macrophage-colony stimulating factor (M-CSF)-induced signaling, c-Src is central to osteoclast activity, but not differentiation. We find Lyn, another member of Src family kinases (SFK) is, in contrast, a negative regulator of osteoclastic bone resorption. The absence of Lyn enhances receptor activator of NF-κB ligand (RANKL)-mediated differentiation of osteoclast precursors without affecting proliferation and survival, while its overexpression decreases osteoclast formation. In further contrast to c-Src, Lyn deficiency does not impact the activity of the mature cell. Reflecting increased osteoclast development in vitro, Lyn−/− mice undergo accelerated osteoclastogenesis and bone loss, in vivo, in response to RANKL. Mechanistically, Lyn forms a complex with receptor activator of NF-κB (RANK), the tyrosine phosphatase, SHP-1, and the adapter protein, Grb2-associated binder 2 (Gab2). Upon RANKL exposure, Gab2 phosphorylation, JNK, and NF-κB activation are enhanced in Lyn−/− osteoclasts, all critical events in osteoclast development. We therefore establish that Lyn regulates osteoclast formation and does it in a manner antithetical to that of c-Src. The most pragmatic aspect of our findings is that successful therapeutic inhibition of c-Src, in the context of the osteoclast, will require its stringent targeting.
Toll-like receptor 4 mediates synergism between alcohol and HCV in hepatic oncogenesis involving stem cell marker Nanog
Authors: Machida Keigo , Tsukamoto Hidekazu , Mkrtchyan Hasmik , Duan Lewei , Dynnyk Alla , Liu Helene Minyi , Asahina Kinji , Govindarajan Sugantha , Ray Ratna , Ou Jing-hsiung James , Seki Ekihiro , Deshaies Raymond , Miyake Kensuke , Lai Michael M.-C.
Published: January 2009

Alcohol synergistically enhances the progression of liver disease and the risk for liver cancer caused by hepatitis C virus (HCV). However, the molecular mechanism of this synergy remains unclear. Here, we provide the first evidence that Toll-like receptor 4 (TLR4) is induced by hepatocyte-specific transgenic (Tg) expression of the HCV nonstructural protein NS5A, and this induction mediates synergistic liver damage and tumor formation by alcohol-induced endotoxemia. We also identify Nanog, the stem/progenitor cell marker, as a novel downstream gene up-regulated by TLR4 activation and the presence of CD133/Nanog-positive cells in liver tumors of alcohol-fed NS5A Tg mice. Transplantation of p53-deficient hepatic progenitor cells transduced with TLR4 results in liver tumor development in mice following repetitive LPS injection, but concomitant transduction of Nanog short-hairpin RNA abrogates this outcome. Taken together, our study demonstrates a TLR4-dependent mechanism of synergistic liver disease by HCV and alcohol and an obligatory role for Nanog, a TLR4 downstream gene, in HCV-induced liver oncogenesis enhanced by alcohol.
A combination of unusual transcription factors binds cooperatively to control
Myxococcus xanthus
developmental gene expression
Authors: Mittal Sheenu , Kroos Lee
Published: January 2009

Myxococcus xanthus
is a bacterium that undergoes multicellular development requiring coordinate regulation of multiple signaling pathways. One pathway governs aggregation and sporulation of some cells in a starving population and requires C-signaling, whereas another pathway causes programmed cell death and requires the MazF toxin. In response to starvation, the levels of the bifunctional transcription factor/antitoxin MrpC and its related proteolytic fragment MrpC2 are increased, inhibiting the cell death pathway via direct interaction of MrpC with MazF. Herein, we demonstrate that MrpC2 plays a direct role in the transcriptional response to C-signaling. We show that MrpC2 binds to sequences upstream of the C-signal-dependent
fmgA
promoter. These sequences are present in other C-signal-dependent promoter regions, indicating a general role for MrpC2 in developmental gene regulation. Association of MrpC and/or MrpC2 with the
fmgA
promoter region in vivo requires FruA, a protein that is similar to response regulators of 2-component signal transduction systems, but may not be phosphorylated. DNA binding studies showed that this association likely involves an unusual mechanism for a response regulator in which FruA and MrpC2 bind cooperatively to adjacent sites upstream of the
fmgA
promoter. We propose that this unusual mechanism of combinatorial control allows coordination of morphogenetic C-signaling with starvation signaling and cell death, determining spatiotemporal gene expression and cell fate.
Caloric restriction improves memory in elderly humans
Authors: Witte A. V. , Fobker M. , Gellner R. , Knecht S. , Flöel A.
Published: January 2009

Animal studies suggest that diets low in calories and rich in unsaturated fatty acids (UFA) are beneficial for cognitive function in age. Here, we tested in a prospective interventional design whether the same effects can be induced in humans. Fifty healthy, normal- to overweight elderly subjects (29 females, mean age 60.5 years, mean body mass index 28 kg/m
2
) were stratified into 3 groups: (
i
) caloric restriction (30% reduction), (
ii
) relative increased intake of UFAs (20% increase, unchanged total fat), and (
iii
) control. Before and after 3 months of intervention, memory performance was assessed under standardized conditions. We found a significant increase in verbal memory scores after caloric restriction (mean increase 20%;
P
< 0.001), which was correlated with decreases in fasting plasma levels of insulin and high sensitive C-reactive protein, most pronounced in subjects with best adherence to the diet (all
r
values < −0.8; all
P
values <0.05). Levels of brain-derived neurotrophic factor remained unchanged. No significant memory changes were observed in the other 2 groups. This interventional trial demonstrates beneficial effects of caloric restriction on memory performance in healthy elderly subjects. Mechanisms underlying this improvement might include higher synaptic plasticity and stimulation of neurofacilitatory pathways in the brain because of improved insulin sensitivity and reduced inflammatory activity. Our study may help to generate novel prevention strategies to maintain cognitive functions into old age.
Newborn infants detect the beat in music
Authors: Winkler István , Háden Gábor P. , Ladinig Olivia , Sziller István , Honing Henkjan
Published: January 2009

To shed light on how humans can learn to understand music, we need to discover what the perceptual capabilities with which infants are born. Beat induction, the detection of a regular pulse in an auditory signal, is considered a fundamental human trait that, arguably, played a decisive role in the origin of music. Theorists are divided on the issue whether this ability is innate or learned. We show that newborn infants develop expectation for the onset of rhythmic cycles (the downbeat), even when it is not marked by stress or other distinguishing spectral features. Omitting the downbeat elicits brain activity associated with violating sensory expectations. Thus, our results strongly support the view that beat perception is innate.
Apoplastic effectors secreted by two unrelated eukaryotic plant pathogens target the tomato defense protease Rcr3
Authors: Song Jing , Win Joe , Tian Miaoying , Schornack Sebastian , Kaschani Farnusch , Ilyas Muhammad , van der Hoorn Renier A. L. , Kamoun Sophien
Published: January 2009

Current models of plant–pathogen interactions stipulate that pathogens secrete effector proteins that disable plant defense components known as virulence targets. Occasionally, the perturbations caused by these effectors trigger innate immunity via plant disease resistance proteins as described by the “guard hypothesis.” This model is nicely illustrated by the interaction between the fungal plant pathogenCladosporium fulvumand tomato.C. fulvumsecretes a protease inhibitor Avr2 that targets the tomato cysteine protease Rcr3pim. In plants that carry the resistance protein Cf2, Rcr3pimis required for resistance toC. fulvumstrains expressing Avr2, thus fulfilling one of the predictions of the guard hypothesis. Another prediction of the guard hypothesis has not yet been tested. Considering that virulence targets are important components of defense, different effectors from unrelated pathogens are expected to evolve to disable the same host target. In this study we confirm this prediction using a different pathogen of tomato, the oomycetePhytophthora infestansthat is distantly related to fungi such asC. fulvum. This pathogen secretes an array of protease inhibitors including EPIC1 and EPIC2B that inhibit tomato cysteine proteases. Here we show that, similar to Avr2, EPIC1 and EPIC2B bind and inhibit Rcr3pim. However, unlike Avr2, EPIC1 and EPIC2B do not trigger hypersensitive cell death or defenses on Cf-2/Rcr3pimtomato. We also found that thercr3–3mutant of tomato that carries a premature stop codon in theRcr3gene exhibits enhanced susceptibility toP. infestans, suggesting a role for Rcr3pimin defense. In conclusion, our findings fulfill a key prediction of the guard hypothesis and suggest that the effectors Avr2, EPIC1, and EPIC2B secreted by two unrelated pathogens of tomato target the same defense protease Rcr3pim. In contrast toC. fulvum,P. infestansappears to have evolved stealthy effectors that carry inhibitory activity without triggering plant innate immunity.
Morphological and functional reorganization of rat medial prefrontal cortex in neuropathic pain
Authors: Metz Alexia E. , Yau Hau-Jie , Centeno Maria Virginia , Apkarian A. Vania , Martina Marco
Published: January 2009

Neuropathic pain is a chronic pain that results from lesion or dysfunction of the nervous system. Depression and cognitive decline are often coupled to chronic pain, suggesting the involvement of cortical areas associated with higher cognitive functions. We investigated layer 2/3 pyramidal neurons in acute slices of the contralateral medial prefrontal cortex (mPFC) in the rat spared nerve injury (SNI) model of neuropathic pain and found morphological and functional differences between the mPFC of SNI and sham-operated animals. Basal, but not apical, dendrites of neurons from SNI rats are longer and have more branches than their counterparts in sham-operated animals; spine density is also selectively increased in basal dendrites of neurons from SNI rats; the morphological changes are accompanied by increased contribution to synaptic currents of the NMDA component. Interestingly, the NMDA/AMPA ratio of the synaptic current elicited in mPFC neurons by afferent fiber stimulation shows linear correlation with the rats' tactile threshold in the injured (but not in the contralateral) paw. Our results not only provide evidence that neuropathic pain leads to rearrangement of the mPFC, which may help defining the cellular basis for cognitive impairments associated with chronic pain, but also show pain-associated morphological changes in the cortex at single neuron level.
β2-Adrenoceptor signaling is required for the development of an asthma phenotype in a murine model
Authors: Nguyen Long P. , Lin Rui , Parra Sergio , Omoluabi Ozozoma , Hanania Nicola A. , Tuvim Michael J. , Knoll Brian J. , Dickey Burton F. , Bond Richard A.
Published: January 2009

Chronic regular use of β2-adrenoceptor (β2-AR) agonists in asthma is associated with a loss of disease control and increased risk of death. Conversely, we have found that administration of β2-AR inverse agonists results in attenuation of the asthma phenotype in an allergen-driven murine model. Besides antagonizing agonist-induced signaling and reducing signaling by empty receptors, β-AR inverse agonists can also activate signaling by novel pathways. To determine the mechanism of the β-AR inverse agonists, we compared the asthma phenotype in β2-AR-null and wild-type mice. Antigen challenge of β2-AR-null mice produced results similar to what was observed with chronic β2-AR inverse agonist treatment, namely, reductions in mucous metaplasia, airway hyperresponsiveness (AHR), and inflammatory cells in the lungs. These results indicate that the effects of β2-AR inverse agonists are caused by inhibition of β2-AR signaling rather than by the induction of novel signaling pathways. Chronic administration of alprenolol, a β-blocker without inverse agonist properties, did not attenuate the asthma phenotype, suggesting that it is signaling by empty receptors, rather than agonist-induced β2-AR signaling, that supports the asthma phenotype. In conclusion, our results demonstrate that, in a murine model of asthma, β2-AR signaling is required for the full development of three cardinal features of asthma: mucous metaplasia, AHR, and the presence of inflammatory cells in the lungs.
Ultrafast excited-state isomerization in phytochrome revealed by femtosecond stimulated Raman spectroscopy
Authors: Dasgupta Jyotishman , Frontiera Renee R. , Taylor Keenan C. , Lagarias J. Clark , Mathies Richard A.
Published: January 2009

Photochemical interconversion between the red-absorbing (P
r
) and the far-red-absorbing (P
fr
) forms of the photosensory protein phytochrome initiates signal transduction in bacteria and higher plants. The P
r
-to-P
fr
transition commences with a rapid
Z
-to-
E
photoisomerization at the C
15

C
16
methine bridge of the bilin prosthetic group. Here, we use femtosecond stimulated Raman spectroscopy to probe the structural changes of the phycocyanobilin chromophore within phytochrome Cph1 on the ultrafast time scale. The enhanced intensity of the C
15
–H hydrogen out-of-plane (HOOP) mode, together with the appearance of red-shifted C

C stretch and N

H in-plane rocking modes within 500 fs, reveal that initial distortion of the C
15

C
16
bond occurs in the electronically excited I* intermediate. From I*, 85% of the excited population relaxes back to P
r
in 3 ps, whereas the rest goes on to the Lumi-R photoproduct consistent with the 15% photochemical quantum yield. The C
15
–H HOOP and skeletal modes evolve to a Lumi-R-like pattern after 3 ps, thereby indicating that the C
15

C
16
Z
-to-
E
isomerization occurs on the excited-state surface.
Design of 240,000 orthogonal 25mer DNA barcode probes
Authors: Xu Qikai , Schlabach Michael R. , Hannon Gregory J. , Elledge Stephen J.
Published: January 2009

DNA barcodes linked to genetic features greatly facilitate screening these features in pooled formats using microarray hybridization, and new tools are needed to design large sets of barcodes to allow construction of large barcoded mammalian libraries such as shRNA libraries. Here we report a framework for designing large sets of orthogonal barcode probes. We demonstrate the utility of this framework by designing 240,000 barcode probes and testing their performance by hybridization. From the test hybridizations, we also discovered new probe design rules that significantly reduce cross-hybridization after their introduction into the framework of the algorithm. These rules should improve the performance of DNA microarray probe designs for many applications.
Yeast telomere capping protein Stn1 overrides DNA replication control through the S phase checkpoint
Authors: Gasparyan Hovik J. , Xu Ling , Petreaca Ruben C. , Rex Alexandra E. , Small Vanessa Y. , Bhogal Neil S. , Julius Jeffrey A. , Warsi Tariq H. , Bachant Jeff , Aparicio Oscar M. , Nugent Constance I.
Published: January 2009

Telomere integrity is maintained through end-protection proteins that block nuclease degradation and prevent telomeres from being recognized as DNA breaks. Although less well understood, end protection proteins may also play a role in facilitating telomere replication. Here, we show that overproduction (OP) of the yeast telomere capping protein Stn1 makes cells highly sensitive to the replication inhibitors hydroxyurea (HU) and methyl-methane sulfonate (MMS). Unexpectedly, this sensitivity corresponds with Stn1 OP blocking most, if not all, aspects of the S phase checkpoint. The checkpoint kinase Rad53 is phosphorylated with normal timing in Stn1 OP cells, indicating Stn1 does not interfere with signaling steps involved in activating the checkpoint. Part of the role of Stn1 in telomere integrity is mediated through the Pol12 subunit of DNA polymerase α (Polα). We show that overproduced Stn1 generally associates with chromosomes in HU treated and untreated cells, and, remarkably, Stn1 chromosome binding and OP checkpoint defects are rescued in
pol12
mutants. We propose Stn1 normally promotes Polα activity at telomeres but can be recruited through Pol12 to nontelomeric sites when overproduced. During replication stress, the mislocalized Stn1 may inappropriately promote Polα in a manner that interferes with Rad53 effector mechanisms controlling replication fork integrity.
Splice-site pairing is an intrinsically high fidelity process
Authors: Fox-Walsh Kristi L. , Hertel Klemens J.
Published: January 2009

The extensive alternative splicing in higher eukaryotes has initiated a debate whether alternative mRNA isoforms are generated by an inaccurate spliceosome or are the consequence of highly degenerate splice sites within the human genome. Here, we established a quantitative assay to evaluate the accuracy of splice-site pairing by determining the number of incorrect exon-skipping events made from constitutively spliced pre-mRNA transcripts. We demonstrate that the spliceosome pairs exons with an astonishingly high degree of accuracy that may be limited by the quality of pre-mRNAs generated by RNA pol II. The error rate of exon pairing is increased by the effects of the neurodegenerative disorder spinal muscular atrophy because of reduced levels of
Survival of Motor Neuron
, a master assembler of spliceosomal components. We conclude that all multi-intron-containing genes are alternatively spliced and that the reduction of SMN results in a general splicing defect that is mediated through alterations in the fidelity of splice-site pairing.
Sport and alcohol: An emergency department study in Switzerland
Authors: Gmel Gerhard , Kuendig Hervé , Daeppen Jean‐Bernard
Published: January 2009

The aim of the present study was to empirically determine whether: (a) sport injuries were associated with alcohol consumption before the injury (acute intake) and with usual consumption patterns (chronic high intake and heavy intake on single occasions); (b) the risk of sport injuries related to alcohol consumption differs from that of other injuries; and (c) there are differences between the sexes and between types of sport. Data from 8694 patients attending the emergency department of Lausanne University Hospital between 1 January 2003 and 30 June 2004 were analysed. Of those patients, 4861 came to the hospital because of an injury and 885 patients were identified as having a sport injury (18.2%). Logistic regression was used to estimate the odds ratios of injury relating to alcohol consumption. With increasingly acute intake, the risk of sport and other injuries increased (sports injury and alcohol use in the 6 h before injury compared with no use: odds ratio=4.29, 7.46, and 14.75 for low, medium, and high alcohol use among women, and 2.81, 3.39, and 1.64 for low, medium, and high alcohol use among men). Alcohol consumption was associated with an increasingly higher risk of sport injuries compared with other injuries among women (consumption 6 h before injury: odds ratio=1.12, 1.23, and 1.56 for low, medium, and high alcohol use), but not men (odds ratio=1.17, 0.83, and 0.23 for low, medium, and high alcohol use). Regarding usual consumption patterns, those men and women injured while exercising were more often at‐risk drinkers (men: 44%; women: 25%) compared with those injured during other activities (men: 37%; women: 13%). The results indicate that both men and women, but particularly women, should not practise sports after alcohol ingestion. The study raises questions as to whether sport should be generally promoted as an alternative to alcohol consumption in prevention programmes. Whereas some sports seem to be protective (e.g. endurance and fitness sport) for risky alcohol use, the majority are not. It is important to note, however, that we do not dismiss the beneficial effects of practising for an individual's health. The other positive aspect of practising, namely interacting socially with others, may come at the price of an increased alcohol use, particularly in a “wet” culture like Switzerland where any social contact is often accompanied by alcohol consumption.
Elite athletes’ duty to provide information on their whereabouts: Justifiable anti‐doping work or an indefensible surveillance regime?
Authors: Hanstad Dag Vidar , Loland Sigmund
Published: January 2009

In this article, we explain and reflect critically upon the athlete whereabouts reporting system in top‐level sports initiated by the World Anti‐Doping Agency (WADA). This system makes it compulsory for athletes who are in a registered testing pool in their national and/or international federation to submit information about their whereabouts. In this way, athletes are required to be available for a no advance notice doping test throughout the year. If an athlete provides incorrect information or cannot be found when a no advance notice test is supposed to be taken (a missed test), he or she may be given a warning. In most sports and national anti‐doping regulations, three such warnings within 18 months may be regarded as a violation of the doping regulations and may lead to exclusion from sport for between 3 months and 2 years. The system is controversial. In this article, we examine the key objections to the system and, more specifically, objections connected to ideas of justice and athletes’ autonomy and right to self‐determination. The argument will be a practical ethical one informed by a survey on attitudes towards the whereabouts system carried out among 236 athletes belonging to the registered testing pool in Norway. We conclude that if the basic principles of anti‐doping work are accepted, WADA's whereabouts reporting system represents nothing other than an efficient extension of this work.
Human CD4+ T cell recent thymic emigrants are identified by protein tyrosine kinase 7 and have reduced immune function
Authors: Haines Christopher J. , Giffon Thierry D. , Lu Li-Sheng , Lu Xiaowei , Tessier-Lavigne Marc , Ross Douglas T. , Lewis David B.
Published: January 2009

CD4+ recent thymic emigrants (RTEs) comprise a clinically and immunologically important T cell population that indicates thymic output and that is essential for maintaining a diverse αβ–T cell receptor (TCR) repertoire of the naive CD4+ T cell compartment. However, their frequency and function are poorly understood because no known surface markers distinguish them from older non-RTE naive CD4+ T cells. We demonstrate that protein tyrosine kinase 7 (PTK7) is a novel marker for human CD4+ RTEs. Consistent with their recent thymic origin, human PTK7+ RTEs contained higher levels of signal joint TCR gene excision circles and were more responsive to interleukin (IL)-7 compared with PTK7− naive CD4+ T cells, and rapidly decreased after complete thymectomy. Importantly, CD4+ RTEs proliferated less and produced less IL-2 and interferon-γ than PTK7− naive CD4+ T cells after αβ-TCR/CD3 and CD28 engagement. This immaturity in CD4+ RTE effector function may contribute to the reduced CD4+ T cell immunity observed in contexts in which CD4+ RTEs predominate, such as in the fetus and neonate or after immune reconstitution. The ability to identify viable CD4+ RTEs by PTK7 staining should be useful for monitoring thymic output in both healthy individuals and in patients with genetic or acquired CD4+ T cell immunodeficiencies.
Differential rates of replacement of human dermal dendritic cells and macrophages during hematopoietic stem cell transplantation
Authors: Haniffa Muzlifah , Ginhoux Florent , Wang Xiao-Nong , Bigley Venetia , Abel Michal , Dimmick Ian , Bullock Sarah , Grisotto Marcos , Booth Trevor , Taub Peter , Hilkens Catharien , Merad Miriam , Collin Matthew
Published: January 2009

Animal models of hematopoietic stem cell transplantation have been used to analyze the turnover of bone marrow–derived cells and to demonstrate the critical role of recipient antigen-presenting cells (APC) in graft versus host disease (GVHD). In humans, the phenotype and lineage relationships of myeloid-derived tissue APC remain incompletely understood. It has also been proposed that the risk of acute GVHD, which extends over many months, is related to the protracted survival of certain recipient APC. Human dermis contains three principal subsets of CD45+HLA-DR+ cells: CD1a+CD14− DC, CD1a−CD14+ DC, and CD1a−CD14+FXIIIa+ macrophages. In vitro, each subset has characteristic properties. After transplantation, both CD1a+ and CD14+ DC are rapidly depleted and replaced by donor cells, but recipient macrophages can be found in GVHD lesions and may persist for many months. Macrophages isolated from normal dermis secrete proinflammatory cytokines. Although they stimulate little proliferation of naive or memory CD4+ T cells, macrophages induce cytokine expression in memory CD4+ T cells and activation and proliferation of CD8+ T cells. These observations suggest that dermal macrophages and DC are from distinct lineages and that persistent recipient macrophages, although unlikely to initiate alloreactivity, may contribute to GVHD by sustaining the responses of previously activated T cells.
The prognostic value of repeated measurement of N‐terminal pro‐B‐type natriuretic peptide in patients with chronic heart failure due to left ventricular systolic dysfunction
Authors: Kubánek Miloš , Goode Kevin M. , Lánská Věra , Clark Andrew L. , Cleland John G.F.
Published: January 2009

Aims

Decreased N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) during treatment of chronic heart failure (CHF) is associated with improved prognosis. However, there is lack of data from community‐based HF programmes. We hypothesized that plasma levels of NT‐proBNP, measured after optimization of pharmacotherapy in patients with CHF, may provide independent prognostic information when compared with baseline values and conventional prognostic markers.

Methods and results

N‐terminal pro‐B‐type natriuretic peptide was measured in 354 patients with CHF and left ventricular ejection fraction <45%, who had recently been enrolled in a community‐based HF programme. Patients underwent a 6 min walk test and clinical, echocardiographic and laboratory examinations. Pharmacotherapy was optimized; 318 patients survived until the second examination and measurement of NT‐proBNP, which was performed between the 4th and 6th month of follow‐up. During a median follow‐up of 38.8 months, 125 patients died. Follow‐up log NT‐proBNP was a better predictor of death than either baseline log NT‐proBNP or change in NT‐proBNP (χ2: 46.5 vs. 30.4 and 12.5, all P < 0.001). N‐terminal pro‐B‐type natriuretic peptide was consistently the strongest independent prognostic marker at predicting death or unplanned cardiovascular hospitalizations after baseline or follow‐up assessment.

Conclusion

The measurement of NT‐proBNP after optimization of pharmacotherapy provides stronger prognostic information than either the baseline value, the change in NT‐proBNP, or other conventional methods of assessment.
The climate
prediction
.net BBC climate change experiment: design of the coupled model ensemble
Authors: Frame D.J , Aina T , Christensen C.M , Faull N.E , Knight S.H.E , Piani C , Rosier S.M , Yamazaki K , Yamazaki Y , Allen M.R
Published: January 2009

Perturbed physics experiments are among the most comprehensive ways to address uncertainty in climate change forecasts. In these experiments, parameters and parametrizations in atmosphere–ocean general circulation models are perturbed across ranges of uncertainty, and results are compared with observations. In this paper, we describe the largest perturbed physics climate experiment conducted to date, the British Broadcasting Corporation (BBC) climate change experiment, in which the physics of the atmosphere and ocean are changed, and run in conjunction with a forcing ensemble designed to represent uncertainty in past and future forcings, under the A1B Special Report on Emissions Scenarios (SRES) climate change scenario.
ENGINEERING IMAGING: USING PARTICLE IMAGE VELOCIMETRY TO SEE PHYSIOLOGY IN A NEW LIGHT
Authors: Fouras Andreas , Dusting Jonathan , Sheridan John , Kawahashi Masaaki , Hirahara Hiroyuki , Hourigan Kerry
Published: January 2009

Despite the array of sophisticated imaging techniques available for biological applications, none of the standard biomedical techniques adequately provides the capability to measure motion and flow. Those techniques currently in use are particularly lacking in spatial and temporal resolution.

Herein, we introduce the technique of particle image velocimetry. This technique is a well‐established tool in engineering research and industry. Particle image velocimetry is continuing to develop and has an increasing number of variants.

Three case studies are presented: (i) the use of microparticle image velocimetry to study flow generated by high‐frequency oscillatory ventilation in a human airway model; (ii) the use of stereoparticle image velocimetry to study stirred cell and tissue culture devices; and (iii) a three‐dimensional X‐ray particle image velocimetry technique used to measure flow in an in vitro vascular flow model.

The case studies highlight the vast potential of applying the engineering technique of particle image velocimetry and its many variants to current research problems in physiology.
High‐pitched breath sounds indicate airflow limitation in asymptomatic asthmatic children
Authors: HABUKAWA Chizu , NAGASAKA Yukio , MURAKAMI Katsumi , TAKEMURA Tsukasa
Published: January 2009

Background and objective:  Asthmatic children may have airway dysfunction even when asymptomatic, indicating that their long‐term treatment is less than optimal. Although airway dysfunction can be identified on lung function testing, performing these tests can be difficult in infants. We studied whether breath sounds reflect subtle airway dysfunction in asthmatic children.

Methods:  The highest frequency of inspiratory breaths sounds (HFI) and the highest frequency of expiratory breath sounds (HFE) were measured in 131 asthmatic children while asymptomatic and with no wheezes for more than 2 weeks. No child was being treated with inhaled corticosteroids (ICS). Breath sounds were recorded and analysed by sound spectrography and compared with spirometric parameters. After initial evaluation, cases with more than step 2 (mild persistent) asthma were treated using inhaled fluticasone (100–200 µg/day) for 1 month, and then breath sound analysis and pulmonary function testing were repeated.

Results:  On initial evaluation, HFI correlated with the percentage of predicted FEF50 (%FEF50), (r = −0.45, P < 0.001), the percentage of predicted FEF75 (%FEF75) (r = −0.456, P < 0.001), and FEV1 as a percentage of FVC (FEV1/FVC (%)) (r = −0.32, P < 0.001). HFI did not correlate with the percentage of predicted PEF (%PEF). The 69 children with lower than normal %FEF50 were then treated with ICS. The %FEF50 and %FEF75 improved after ICS treatment, and increases in %FEF50 (P < 0.005) correlated with decreases in HFI (P < 0.001).

Conclusions:  Higher HFI in asymptomatic asthmatic children may indicate small airway obstruction. Additional ICS treatment may improve the pulmonary function indices representing small airway function with simultaneous HFI decreases in such patients.