bluuebunny/crossref_metadata_2025 huggingface dataset:
Activation of anterior cingulate cortex produces inhibitory effects on noxious mechanical and electrical stimuli‐evoked responses in rat spinal WDR neurons
Authors: Mal Jiu‐Hong , Xiaol Tie‐Hui , Changl Chong‐Wang , Gaol Li , Wangl Xue‐Lian , Gaol Guo‐Dong , Yul Yao‐Qing
Published: May 2011

In present study, in vivo electrophysiological techniques were applied to examine the effects of anterior cingulate cortex (ACC) activation on mechanical and electrical stimuli‐evoked responses in rat spinal cord wide‐dynamic‐range (WDR) neurons. We found that bilateral ACC electrical stimulation (100 Hz, 20 V, 20 s) had different effects on neuronal responses to brush, pressure and pinch stimuli (10 s). The brush‐evoked neuronal responses at baseline, post 1 min and post 5 min were 60.8±15.0, 59.2±15.4 and 60.0±19.3 spikes/10 s, respectively (n =10, P >0.05 vs. baseline). The pressure‐evoked neuronal responses at baseline, post 1 min and post 5 min were 77.8±11.9, 38.0±7.8 and 45.8±7.6 spikes/10 s, respectively (n =10, P <0.05 vs. baseline). The pinch‐evoked neuronal responses at baseline, post 1 min and post 5 min were 137.6±16.7, 62.6±17.5 and 68.8±15.0 spikes/10 s, respectively (n =10, P <0.05 vs. baseline). Furthermore, ACC stimulation generated distinct effects on the different components of wind‐up response. The total numbers of late response (LR) and after‐discharge (AD), but not early response (ER), significantly decreased. Collectively, the present study demonstrated that short‐term ACC activation could generate long‐term inhibitory effects on the responses of WDR neurons to noxious mechanical (pressure and pinch) and electrical stimuli. The results indicated that ACC activation could negatively regulate noxious information ascending from spinal cord with long‐term effect, providing potential neuronal substrate for the modulation of ACC activation on nociception.
A loess–paleosol record of climate and glacial history over the past two glacial–interglacial cycles (~ 150 ka), southern Jackson Hole, Wyoming
Authors: Pierce Kenneth L. , Muhs Daniel R. , Fosberg Maynard A. , Mahan Shannon A. , Rosenbaum Joseph G. , Licciardi Joseph M. , Pavich Milan J.
Published: May 2011

Loess accumulated on a Bull Lake outwash terrace of Marine Oxygen Isotope Stage 6 (MIS 6) age in southern Jackson Hole, Wyoming. The 9 m section displays eight intervals of loess deposition (Loess 1 to Loess 8, oldest), each followed by soil development. Our age-depth model is constrained by thermoluminescence, meteoric 10Be accumulation in soils, and cosmogenic 10Be surface exposure ages. We use particle size, geochemical, mineral-magnetic, and clay mineralogical data to interpret loess sources and pedogenesis. Deposition of MIS 6 loess was followed by a tripartite soil/thin loess complex (Soils 8, 7, and 6) apparently reflecting the large climatic oscillations of MIS 5. Soil 8 (MIS 5e) shows the strongest development. Loess 5 accumulated during a glacial interval (~ 76–69 ka; MIS 4) followed by soil development under conditions wetter and probably colder than present. Deposition of thick Loess 3 (~ 43–51 ka, MIS 3) was followed by soil development comparable with that observed in Soil 1. Loess 1 (MIS 2) accumulated during the Pinedale glaciation and was followed by development of Soil 1 under a semiarid climate. This record of alternating loess deposition and soil development is compatible with the history of Yellowstone vegetation and the glacial flour record from the Sierra Nevada.
Exact tensor closures for the three-dimensional Jeffery's equation
Authors: MONTGOMERY-SMITH STEPHEN , HE WEI , JACK DAVID A. , SMITH DOUGLAS E.
Published: May 2011

This paper presents an exact formula for calculating the fourth-moment tensor from the second-moment tensor for the three-dimensional Jeffery's equation. Although this approach falls within the category of a moment tensor closure, it does not rely upon an approximation, either analytic or curve fit, of the fourth-moment tensor as do previous closures. This closure is orthotropic in the sense of Cintra & Tucker (J. Rheol., vol. 39, 1995, p. 1095), or equivalently, a natural closure in the sense of Verleye & Dupret (Developments in Non-Newtonian Flow, 1993, p. 139). The existence of these explicit formulae has been asserted previously, but as far as the authors know, the explicit forms have yet to be published. The formulae involve elliptic integrals, and are valid whenever fibre orientation was isotropic at some point in time. Finally, this paper presents the fast exact closure, a fast and in principle exact method for solving Jeffery's equation, which does not require approximate closures nor the elliptic integral computation.
Pitfalls in the management of monaural deafness
Authors: Feng Y-M , Wu Y-Q , Zhou H-Q , Shi H-B
Published: May 2011

Objective:

We report a patient who underwent cochlear implantation in an ear with long-term deafness, after an acoustic neuroma had been removed surgically from the other, hitherto good ear and the cochlear nerve had subsequently been resected to relieve severe tinnitus.

Method:

Case report.

Results:

The patient could not tolerate the cochlear implant, because of a moderate headache due to the stimulation level necessary for environmental sound discrimination.

Conclusion:

Cochlear implantation in patients with long-term deafness should be considered carefully, even if deafness is monaural.
Tiberius and the Heavenly Twins
Authors: Champlin Edward
Published: May 2011

This paper aims to illustrate the practical application of myth in public life under the early Principate. It begins by sketching the deep historical affection of the people of Rome for the twins Castor and Pollux, and the great posthumous popularity of Nero Claudius Drusus for generations after his death in 9b.c. Concentrating on the dedicatory inscription of the Temple of Castor and Pollux in Rome, the paper argues that Tiberius Caesar, notoriously addicted to mythology, crafted a potent public association between the heavenly twins and himself and his brother Drusus, and it goes on to examine the effect of that association.
Subsemigroups of transitive semigroups
Authors: MATHERON ÉTIENNE
Published: May 2011

Let Γ be a topological semigroup acting on a topological space X, and let Γ0 be a subsemigroup of Γ. We give general conditions ensuring that Γ and Γ0 have the same transitive points.
Can RoTEM®analysis be applied for haemostatic monitoring in paediatric congenital heart surgery?
Authors: Andreasen Jo Bønding , Hvas Anne-Mette , Christiansen Kirsten , Ravn Hanne Berg
Published: May 2011

Background

Successful management of bleeding disorders after congenital heart surgery requires detection of specific coagulation disturbances. Whole-blood rotation thromboelastometry (RoTEM®) provides continuous qualitative haemostatic profiles, and the technique has shown promising results in adult cardiac surgery.

Setting

To compare the performance of RoTEM®with that of conventional coagulation tests in children, we conducted a descriptive study in children undergoing congenital cardiac surgery. For that purpose, 60 children were enrolled and had blood samples taken before, immediately after, and 1 day after surgery. Conventional coagulation tests included: activated partial thromboplastin time, prothrombin time, fibrinogen, fibrin D-dimer, thrombin clotting time, factor XIII, and platelet count.

Results

Post-surgical haemostatic impairment was present to some degree in all children, as seen by pronounced changes in activated partial thromboplastin time, prothrombin time, thrombin clotting time, and platelet count, as well as RoTEM®analysis. RoTEM®showed marked changes in clotting time – prolonged by 7–18% – clot formation time – prolonged by 46–71% – maximum clot firmness – reduced by 10–19%, and maximum velocity – reduced by 29–39%. Comparison of the two techniques showed that conventional coagulation tests and RoTEM®performed equally well with regard to negative predictive values for excessive post-operative drain production – more than 20 millilitres per kilogram per 24 hours after surgery – with an area under the curve of approximately 0.65.

Conclusion

RoTEM®can detect haemostatic impairments in children undergoing cardiac surgery and the method should be considered as a supplement in the perioperative care of the children where targeted transfusion therapy is necessary to avoid volume overload.
Severe physical violence between intimate partners during pregnancy: a risk factor for early cessation of exclusive breast-feeding
Authors: Moraes Claudia L , de Oliveira Alessandra SD , Reichenheim Michael E , Lobato Gustavo
Published: May 2011

Objective

To investigate the role of severe physical violence during pregnancy (SPVP) between intimate partners in early cessation of exclusive breast-feeding (EBF).

Design

A health services survey. The revised Conflict Tactics Scale was used to characterize SPVP; premature breast-feeding cessation was identified using a current status data approach, which was based on the information reported from food recall during the preceding 7 d. The cumulative hazard function was estimated by complementary log–log transformation models, which allowed the ensuing estimation of early breast-feeding cessation rates in different age groups and the ratio of rates of weaning between women exposed and not exposed to violence.

Setting

Five large public primary health-care facilities of Rio de Janeiro, Brazil.

Subjects

The sample comprised 811 randomly selected mothers of children under 5 months of age who were waiting to be consulted.

Results

SPVP is an independent risk factor of cessation of EBF since, after controlling for socio-economic, demographic, reproductive and lifestyle variables, women exposed to violence presented an incidence density that was 31 % higher than those who were not exposed (hazard ratio = 1·30, 95 % CI 1·01, 1·69).

Conclusions

The findings corroborate the hypothesis that SPVP is an important risk factor for EBF. This indicates the need for incentives to adequately train health-care personnel in dealing with lactating women in order to gain a broader view of breast-feeding beyond the biological aspects of lactation, including the maternal psychological dimension.
Parental eating attitudes and indicators of healthy eating in a longitudinal randomized dietary intervention trial (the STRIP study)
Authors: Talvia Sanna , Räsänen Leena , Lagström Hanna , Anglè Susanna , Hakanen Maarit , Aromaa Minna , Sillanmäki Lauri , Saarinen Maiju , Simell Olli
Published: May 2011

Objective

To examine the effects of child-oriented dietary intervention on parental eating attitudes and dietary behaviour.

Design

In the prospective, randomized Special Turku Coronary Risk Factor Intervention Project for Children (the STRIP study), a cohort of Finnish families took part in a nutritional intervention trial focused on the quality of their children's fat intake since the age of 8 months. Health-related and hedonic eating attitudes of the parents were measured after 10 years of dietary intervention using a validated Health and Taste Attitude Scales (HTAS) questionnaire (n 660). Parents’ eating behaviour was studied using a 1 d food record (n 491).

Setting

Finland.

Subjects

Mothers and fathers (n 660) of the STRIP children.

Results

The parents of the intervention families had a higher level of interest in healthy eating compared with control parents. The interest in natural products or hedonic eating attitudes did not differ between the groups. The parents’ general health interest was associated with low saturated fat intake, fruit and vegetable consumption, fibre intake and seeking pleasure in eating, but it was not associated with BMI. The intervention also improved the quality of dietary fat among parents with the lowest level of interest in healthy eating.

Conclusions

Parents’ general health interest was associated with regular dietary counselling as well as with healthier food choice behaviour. However, the dietary intervention that focused especially on the quality of the child's fat intake also enhanced specific changes in the family's fat consumption without a high level of interest in healthy eating.
Quantitative constraint on footwall rotations at the 15°45′N oceanic core complex, Mid‐Atlantic Ridge: Implications for oceanic detachment fault processes
Authors: MacLeod C. J. , Carlut J. , Escartín J. , Horen H. , Morris A.
Published: May 2011

The subsurface geometry of detachment faults at slow spreading mid‐ocean ridges is debated: are they planar features that form and slip at low angles, as often inferred for their continental equivalents, or do they initiate at steep angles and then flatten in response to flexural unloading as displacement proceeds, as predicted in “rolling hinge” conceptual models? An essential difference is that significant rotation of the footwall should occur in the rolling hinge but not the planar fault model. This can be tested using paleomagnetism. Previous attempts to address this question have relied upon data from azimuthally unoriented drill cores. Although results are consistent with large rotations having occurred, these interpretations are very nonunique, and other solutions that require minimal rotations are equally permissible. We here present a rigorous analysis of paleomagnetic and structural data from a unique set of azimuthally oriented cores, collected using a seabed rock drill, from the 15°45′N oceanic core complex on the Mid‐Atlantic Ridge. By considering the full paleomagnetic remanence vector in combination with kinematic data from the detachment fault shear zone we are able to quantitatively constrain the geometrically permissible axes and magnitudes of rotation of the detachment fault footwall, for the first time without having to make a priori assumptions about the orientation of the axis. We show that significant rotations (64° ± 16°) have indeed occurred, about a gently plunging, near‐ridge‐parallel axis, robustly supporting the rolling hinge models. We further discuss the geological implications of this result for oceanic detachment fault processes.
Properties of the dispersion relation in finite one-dimensional photonic crystals
Authors: de Dios-Leyva M. , Drake-Pérez Julio C.
Published: May 2011

Using the transfer-matrix method we have expressed the dispersion relation of a finite, N-period, one-dimensional photonic crystal in terms of a frequency dependent function g(ω) determining important features of the band structure. We have then investigated the similarities and differences between the dispersion relation of a N-period crystal and that of an infinite one for finite and large values of the number N of unit cells. It is shown that in the frequency range where the infinite crystal has a bandgap, the dispersion relation of the finite crystal exhibits a bandgap of zero width for any value of N. The frequency ωC at which the null gap occurs corresponds to a zero of g(ω) and is independent of N. Around ωC and for sufficiently large values of N, the group velocity attains superluminal values. These results are general enough and were used to investigate the effects of finite crystal size on the properties of the zero-n− gap in photonic crystals consisting of alternating layers of right- and left-handed materials. In this case, the frequency at which the null gap occurs is insensitive to geometrical scaling of the structure.
Two-dimensional infrared spectroscopy of isotope-diluted ice Ih
Authors: Perakis Fivos , Widmer Susanne , Hamm Peter
Published: May 2011

We present experimental 2D IR spectra of isotope diluted ice Ih (i.e., the OH stretch mode of HOD in D2O and the OD stretch mode of HOD in H2O) at T = 80 K. The main spectral features are the extremely broad 1-2 excited state transition, much broader than the corresponding 0-1 groundstate transition, as well as the presence of quantum beats. We do not observe any inhomogeneous broadening that might be expected due to proton disorder in ice Ih. Complementary, we perform simulations in the framework of the Lippincott-Schroeder model, which qualitatively reproduce the experimental observations. We conclude that the origin of the observed line shape features is the coupling of the OH-vibrational coordinate with crystal phonons and explain the beatings as a coherent oscillation of the O⋅⋅⋅O hydrogen bond degree of freedom.
At the limit of total silane gas utilization for preparation of high-quality microcrystalline silicon solar cells at high-rate plasma deposition
Authors: Gordijn A. , Pollet-Villard A. , Finger F.
Published: May 2011

It was aimed to find a regime for high-rate deposition of microcrystalline silicon with a silane gas utilization rate close to 100%. It is found that state-of-the art solar cells can be prepared at such conditions. The interdependencies of the relevant deposition parameters were identified in an experimental study in a multidimensional parameter space in which for each condition the μc-Si crystalline volume fraction was optimized to find the “optimum phase mixture.” It is concluded that choice of the deposition pressure has a critical influence on the silane gas utilization rate and deposition rate.
Structural transition in LaVO3/SrVO3 superlattices and its influence on transport properties
Authors: David A. , Frésard R. , Boullay Ph. , Prellier W. , Lüders U. , Janolin P.-E.
Published: May 2011

Measurements of the resistive properties and the lattice parameters of a (LaVO3)[6 unit cells]/(SrVO3)[1 unit cell] superlattice between 10 K and room temperature are presented. A low temperature metallic phase compatible with a Fermi liquid behavior is evidenced. It disappears in the vicinity of a structural transition from a monoclinic to tetragonal phase, in which disorder seems to strongly influence the transport. Our results will enrich the understanding of the electronic properties of complex heterostructures.
Pt(II) complex based phosphorescent organic light emitting diodes with external quantum efficiencies above 20%
Authors: Wang Z. B. , Helander M. G. , Hudson Z. M. , Qiu J. , Wang S. , Lu Z. H.
Published: May 2011

Phosphorescent organic light emitting diodes with >20% external quantum efficiency have been demonstrated for the first time using a cyclometalated Pt(II) complex with a triarylboron group, i.e., acetylacetonato(5-dimesitylboryl-2-(phenyl)pyridyl)platinum(II), or Pt-BppyA. This unprecedented device performance is mainly attributed to the high quantum yield of the Pt(II) complex that is achieved by using a triarylboron moiety as well as to the highly optimized double emission zone device architecture.
Neutron doping effects in epitaxially laterally overgrown n-GaN
Authors: Lee In-Hwan , Polyakov A. Y. , Smirnov N. B. , Govorkov A. V. , Kozhukhova E. A. , Yakimov E. B. , Kolin N. G. , Boiko V. M. , Korulin A. V. , Pearton S. J.
Published: May 2011

Thermal neutron irradiation and annealing effects were studied for undoped n-GaN prepared by epitaxial lateral overgrowth (ELOG). Electron beam induced current (EBIC) imaging and profiling prior to irradiation showed that the residual donor doping in our ELOG samples was about three times higher in the high-dislocation-density ELOG wing than in the low-dislocation-density ELOG window regions. Irradiation with thermal neutrons and subsequent annealing led to greatly improved doping uniformity, as evidenced by EBIC imaging. The neutron transmutation doping avoids the anisotropy of donor incorporation efficiency for different planes during ELOG and provides a uniform doping environment. Capacitance-voltage profiling on such samples showed the presence of electrically active centers with concentration close to the concentration of Ge donors produced by Ga interaction with thermal neutrons.
Communication: Spectroscopic measurements for HfF+ of relevance to the investigation of fundamental constants
Authors: Barker Beau J. , Antonov Ivan O. , Bondybey Vladimir E. , Heaven Michael C.
Published: May 2011

The properties of the HfF+ cation are thought to be well-suited for investigations of the electron electric dipole moment (eEDM) and temporal variations of the fine structure constant. Precision spectroscopic measurements involving the X1Σ+ and low-lying 3Δ1 states have been proposed to measure both. Due to the lack of data for HfF+, the design of these experiments has relied entirely on the predictions of electronic structure calculations. Spectroscopic characterizations of the X1Σ+, 3Δ1, 3Δ2 and 3Δ3 states are reported. The results further support the contention that HfF+ is a viable candidate for eEDM measurements. The spacings between adjacent X1Σ+ and 3Δ1 levels are found to be less favorable for the proposed studies of the fine structure constant.
Systematic variation in the temperature dependence of physiological and ecological traits
Authors: Dell Anthony I. , Pawar Samraat , Savage Van M.
Published: May 2011

To understand the effects of temperature on biological systems, we compile, organize, and analyze a database of 1,072 thermal responses for microbes, plants, and animals. The unprecedented diversity of traits (
n
= 112), species (
n
= 309), body sizes (15 orders of magnitude), and habitats (all major biomes) in our database allows us to quantify novel features of the temperature response of biological traits. In particular, analysis of the rising component of within-species (intraspecific) responses reveals that 87% are fit well by the Boltzmann–Arrhenius model. The mean activation energy for these rises is 0.66 ± 0.05 eV, similar to the reported across-species (interspecific) value of 0.65 eV. However, systematic variation in the distribution of rise activation energies is evident, including previously unrecognized right skewness around a median of 0.55 eV. This skewness exists across levels of organization, taxa, trophic groups, and habitats, and it is partially explained by prey having increased trait performance at lower temperatures relative to predators, suggesting a thermal version of the life-dinner principle—stronger selection on running for your life than running for your dinner. For unimodal responses, habitat (marine, freshwater, and terrestrial) largely explains the mean temperature at which trait values are optimal but not variation around the mean. The distribution of activation energies for trait falls has a mean of 1.15 ± 0.39 eV (significantly higher than rises) and is also right-skewed. Our results highlight generalities and deviations in the thermal response of biological traits and help to provide a basis to predict better how biological systems, from cells to communities, respond to temperature change.
ES cell-derived renewable and functional midbrain dopaminergic progenitors
Authors: Chung Sangmi , Moon Jung-Il , Leung Amanda , Aldrich Daniel , Lukianov Stefan , Kitayama Yui , Park Sara , Li Yan , Bolshakov Vadim Y. , Lamonerie Thomas , Kim Kwang-Soo
Published: May 2011

During early development, midbrain dopaminergic (mDA) neuronal progenitors (NPs) arise from the ventral mesencephalic area by the combined actions of secreted factors and their downstream transcription factors. These mDA NPs proliferate, migrate to their final destinations, and develop into mature mDA neurons in the substantia nigra and the ventral tegmental area. Here, we show that such authentic mDA NPs can be efficiently isolated from differentiated ES cells (ESCs) using a FACS method combining two markers, Otx2 and Corin. Purified Otx2
+
Corin
+
cells coexpressed other mDA NP markers, including FoxA2, Lmx1b, and Glast. Using optimized culture conditions, these mDA NPs continuously proliferated up to 4 wk with almost 1,000-fold expansion without significant changes in their phenotype. Furthermore, upon differentiation, Otx2
+
Corin
+
cells efficiently generated mDA neurons, as evidenced by coexpression of mDA neuronal markers (e.g., TH, Pitx3, Nurr1, and Lmx1b) and physiological functions (e.g., efficient DA secretion and uptake). Notably, these mDA NPs differentiated into a relatively homogenous DA population with few serotonergic neurons. When transplanted into PD model animals, aphakia mice, and 6-OHDA–lesioned rats, mDA NPs differentiated into mDA neurons in vivo and generated well-integrated DA grafts, resulting in significant improvement in motor dysfunctions without tumor formation. Furthermore, grafted Otx2
+
Corin
+
cells exhibited significant migratory function in the host striatum, reaching >3.3 mm length in the entire striatum. We propose that functional and expandable mDA NPs can be efficiently isolated by this unique strategy and will serve as useful tools in regenerative medicine, bioassay, and drug screening.
Soil warming, carbon–nitrogen interactions, and forest carbon budgets
Authors: Melillo Jerry M. , Butler Sarah , Johnson Jennifer , Mohan Jacqueline , Steudler Paul , Lux Heidi , Burrows Elizabeth , Bowles Francis , Smith Rose , Scott Lindsay , Vario Chelsea , Hill Troy , Burton Andrew , Zhou Yu-Mei , Tang Jim
Published: May 2011

Soil warming has the potential to alter both soil and plant processes that affect carbon storage in forest ecosystems. We have quantified these effects in a large, long-term (7-y) soil-warming study in a deciduous forest in New England. Soil warming has resulted in carbon losses from the soil and stimulated carbon gains in the woody tissue of trees. The warming-enhanced decay of soil organic matter also released enough additional inorganic nitrogen into the soil solution to support the observed increases in plant carbon storage. Although soil warming has resulted in a cumulative net loss of carbon from a New England forest relative to a control area over the 7-y study, the annual net losses generally decreased over time as plant carbon storage increased. In the seventh year, warming-induced soil carbon losses were almost totally compensated for by plant carbon gains in response to warming. We attribute the plant gains primarily to warming-induced increases in nitrogen availability. This study underscores the importance of incorporating carbon–nitrogen interactions in atmosphere–ocean–land earth system models to accurately simulate land feedbacks to the climate system.
Apolar surface area determines the efficiency of translocon-mediated membrane-protein integration into the endoplasmic reticulum
Authors: Öjemalm Karin , Higuchi Takashi , Jiang Yang , Langel Ülo , Nilsson IngMarie , White Stephen H. , Suga Hiroaki , von Heijne Gunnar
Published: May 2011

Integral membrane proteins are integrated cotranslationally into the membrane of the endoplasmic reticulum in a process mediated by the Sec61 translocon. Transmembrane α-helices in a translocating polypeptide chain gain access to the surrounding membrane through a lateral gate in the wall of the translocon channel [van den Berg B, et al. (2004)
Nature
427:36–44; Zimmer J, et al. (2008)
Nature
455:936–943; Egea PF, Stroud RM (2010)
Proc Natl Acad Sci USA
107:17182–17187]. To clarify the nature of the membrane-integration process, we have measured the insertion efficiency into the endoplasmic reticulum membrane of model hydrophobic segments containing nonproteinogenic aliphatic and aromatic amino acids. We find that an amino acid’s contribution to the apparent free energy of membrane-insertion is directly proportional to the nonpolar accessible surface area of its side chain, as expected for thermodynamic partitioning between aqueous and nonpolar phases. But unlike bulk-phase partitioning, characterized by a nonpolar solvation parameter of 23 cal/(mol·
Å
2
), the solvation parameter for transfer from translocon to bilayer is 6–10 cal/(mol·
Å
2
), pointing to important differences between translocon-guided partitioning and simple water-to-membrane partitioning. Our results provide compelling evidence for a thermodynamic partitioning model and insights into the physical properties of the translocon.
Electronic phase diagram of high-temperature copper oxide superconductors
Authors: Chatterjee Utpal , Ai Dingfei , Zhao Junjing , Rosenkranz Stephan , Kaminski Adam , Raffy Helene , Li Zhizhong , Kadowaki Kazuo , Randeria Mohit , Norman Michael R. , Campuzano J. C.
Published: May 2011

In order to understand the origin of high-temperature superconductivity in copper oxides, we must understand the normal state from which it emerges. Here, we examine the evolution of the normal state electronic excitations with temperature and carrier concentration in Bi
2
Sr
2
CaCu
2
O

8+
δ

using angle-resolved photoemission. In contrast to conventional superconductors, where there is a single temperature scale
T

c

separating the normal from the superconducting state, the high-temperature superconductors exhibit two additional temperature scales. One is the pseudogap scale
T
∗
, below which electronic excitations exhibit an energy gap. The second is the coherence scale
T
coh
, below which sharp spectral features appear due to increased lifetime of the excitations. We find that
T
∗
and
T
coh
are strongly doping dependent and cross each other near optimal doping. Thus the highest superconducting
T

c

emerges from an unusual normal state that is characterized by coherent excitations with an energy gap.
Endothelium-protective sphingosine-1-phosphate provided by HDL-associated apolipoprotein M
Authors: Christoffersen Christina , Obinata Hideru , Kumaraswamy Sunil B. , Galvani Sylvain , Ahnström Josefin , Sevvana Madhumati , Egerer-Sieber Claudia , Muller Yves A. , Hla Timothy , Nielsen Lars B. , Dahlbäck Björn
Published: May 2011

Protection of the endothelium is provided by circulating sphingosine-1-phosphate (S1P), which maintains vascular integrity. We show that HDL-associated S1P is bound specifically to both human and murine apolipoprotein M (apoM). Thus, isolated human ApoM
+
HDL contained S1P, whereas ApoM
−
HDL did not. Moreover, HDL in

Apom
−/−

mice contains no S1P, whereas HDL in transgenic mice overexpressing human apoM has an increased S1P content. The 1.7-Å structure of the S1P–human apoM complex reveals that S1P interacts specifically with an amphiphilic pocket in the lipocalin fold of apoM. Human ApoM
+
HDL induced S1P
1
receptor internalization, downstream MAPK and Akt activation, endothelial cell migration, and formation of endothelial adherens junctions, whereas apoM
−
HDL did not. Importantly, lack of S1P in the HDL fraction of

Apom
−/−

mice decreased basal endothelial barrier function in lung tissue. Our results demonstrate that apoM, by delivering S1P to the S1P
1
receptor on endothelial cells, is a vasculoprotective constituent of HDL.
Core unit of chemotaxis signaling complexes
Authors: Li Mingshan , Hazelbauer Gerald L.
Published: May 2011

Bacterial chemoreceptors, histidine kinase CheA, and coupling protein CheW form clusters of chemotaxis signaling complexes. In signaling complexes kinase activity is enhanced several hundredfold and placed under receptor control. Activation is necessary to poise enzyme activity such that receptor control has physiologically relevant effects. Thus kinase activation can be considered the underlying core activity of signaling complexes. We defined the minimal physical unit that generates this activity using chemoreceptor Tar from
Escherichia coli
rendered water soluble by insertion into nanodiscs to (
i
) measure saturable binding of CheA and CheW to the smallest kinase-activating groups of receptor dimers and (
ii
) purify and characterize core units of signaling complexes. Purified complexes activated kinase almost as well as signaling complexes formed on arrays of receptors in isolated native membrane. Purified complexes contained two receptor trimers of dimers and two CheW for each CheA dimer, consistent with the approximately 1∶1 CheA∶CheW ratio determined by binding measurements. The 2∶2∶1 stoichiometry implied that CheA dimers, the enzymatically active form, connect two chemoreceptor trimers of dimers by interaction of one CheA protomer and a CheW with each trimer, an organization for which specific molecular interactions have previously been identified. The core unit associates six receptor dimers with a CheA dimer, providing sufficient capacity to account for much of the cooperativity and interdimer influence observed experimentally. We conclude that the 2∶2∶1 organization is the core structural and functional unit of chemotaxis signaling complexes and postulate that hexagonal arrays characteristic of signaling complexes are built from this unit.
Interaction of a G protein with an activated receptor opens the interdomain interface in the alpha subunit
Authors: Van Eps Ned , Preininger Anita M. , Alexander Nathan , Kaya Ali I. , Meier Scott , Meiler Jens , Hamm Heidi E. , Hubbell Wayne L.
Published: May 2011

In G-protein signaling, an activated receptor catalyzes GDP/GTP exchange on the
G

α

subunit of a heterotrimeric G protein. In an initial step, receptor interaction with
G

α

acts to allosterically trigger GDP release from a binding site located between the nucleotide binding domain and a helical domain, but the molecular mechanism is unknown. In this study, site-directed spin labeling and double electron–electron resonance spectroscopy are employed to reveal a large-scale separation of the domains that provides a direct pathway for nucleotide escape. Cross-linking studies show that the domain separation is required for receptor enhancement of nucleotide exchange rates. The interdomain opening is coupled to receptor binding via the C-terminal helix of
G

α

, the extension of which is a high-affinity receptor binding element.
PTEN-inducible kinase 1 (PINK1)/Park6 is indispensable for normal heart function
Authors: Billia Filio , Hauck Ludger , Konecny Filip , Rao Vivek , Shen Jie , Mak Tak Wah
Published: May 2011

Oxidative stress is caused by an imbalance between reactive oxygen species (ROS) production and the ability of an organism to eliminate these toxic intermediates. Mutations in PTEN-inducible kinase 1 (PINK1) link mitochondrial dysfunction, increased sensitivity to ROS, and apoptosis in Parkinson's disease. Whereas PINK1 has been linked to the regulation of oxidative stress, the exact mechanism by which this occurs has remained elusive. Oxidative stress with associated mitochondrial dysfunction leads to cardiac dysfunction and heart failure (HF). We hypothesized that loss of PINK1 in the heart would have deleterious consequences on mitochondrial function. Here, we observed that PINK1 protein levels are markedly reduced in end-stage human HF. We also report that PINK1 localizes exclusively to the mitochondria. PINK1
−/−
mice develop left ventricular dysfunction and evidence of pathological cardiac hypertrophy as early as 2 mo of age. Of note, PINK1
−/−
mice have greater levels of oxidative stress and impaired mitochondrial function. There were also higher degrees of fibrosis, cardiomyocyte apoptosis, and a reciprocal reduction in capillary density associated with this baseline cardiac phenotype. Collectively, our in vivo data demonstrate that PINK1 activity is crucial for postnatal myocardial development, through its role in maintaining mitochondrial function, and redox homeostasis in cardiomyocytes. In conclusion, PINK1 possesses a distinct, nonredundant function in the surveillance and maintenance of cardiac tissue homeostasis.
Recognition of the centromere-specific histone Cse4 by the chaperone Scm3
Authors: Cho Uhn-Soo , Harrison Stephen C.
Published: May 2011

A specialized nucleosome is a component of all eukaryotic kinetochores. The core of this nucleosome contains a centromere-specific histone, CENP-A (the Cse4 gene product in budding yeast), instead of the usual H3. Assembly of a centromeric nucleosome depends on a specific chaperone, called Scm3 in yeast and HJURP in higher eukaryotes. We describe here the structure of a complex formed by an N-terminal fragment of Scm3 with the histone-fold domains of Cse4, and H4, all prepared as recombinant proteins derived from the budding yeast
Kluyveromyces lactis
. The contacts of Scm3 with Cse4 explain its selectivity for the centromere-specific histone; key residues at the interface are conserved in HJURP, indicating a common mechanism for centromeric-histone deposition. We also report the structure of a (Cse4 : H4)
2
heterotetramer; comparison with the structure of the Scm3:Cse4:H4 complex shows that tetramer formation and DNA-binding require displacement of Scm3 from the nucleosome core. The two structures together suggest that specific contacts between the chaperone and Cse4, rather than an altered overall structure of the nucleosome core, determine the selective presence of Cse4 at centromeres.
Helicase-DNA polymerase interaction is critical to initiate leading-strand DNA synthesis
Authors: Zhang Huidong , Lee Seung-Joo , Zhu Bin , Tran Ngoc Q. , Tabor Stanley , Richardson Charles C.
Published: May 2011

Interactions between gene 4 helicase and gene 5 DNA polymerase (gp5) are crucial for leading-strand DNA synthesis mediated by the replisome of bacteriophage T7. Interactions between the two proteins that assure high processivity are known but the interactions essential to initiate the leading-strand DNA synthesis remain unidentified. Replacement of solution-exposed basic residues (K587, K589, R590, and R591) located on the front surface of gp5 with neutral asparagines abolishes the ability of gp5 and the helicase to mediate strand-displacement synthesis. This front basic patch in gp5 contributes to physical interactions with the acidic C-terminal tail of the helicase. Nonetheless, the altered polymerase is able to replace gp5 and continue ongoing strand-displacement synthesis. The results suggest that the interaction between the C-terminal tail of the helicase and the basic patch of gp5 is critical for initiation of strand-displacement synthesis. Multiple interactions of T7 DNA polymerase and helicase coordinate replisome movement.
Platelet activation attracts a subpopulation of effector monocytes to sites of Leishmania major infection
Authors: Goncalves Ricardo , Zhang Xia , Cohen Heather , Debrabant Alain , Mosser David M.
Published: May 2011

Leishmania species trigger a brisk inflammatory response and efficiently induce cell-mediated immunity. We examined the mechanisms whereby leukocytes were recruited into lesions after Leishmania major infection of mice. We found that a subpopulation of effector monocytes expressing the granulocyte marker GR1 (Ly6C) is rapidly recruited into lesions, and these monocytes efficiently kill L. major parasites. The recruitment of this subpopulation of monocytes depends on the chemokine receptor CCR2 and the activation of platelets. Activated platelets secrete platelet-derived growth factor, which induces the rapid release of CCL2 from leukocytes and mesenchymal cells. This work points to a new role for platelets in host defense involving the selective recruitment of a subpopulation of effector monocytes from the blood to efficiently kill this intracellular parasite.
THE FAR-ULTRAVIOLET “CONTINUUM” IN PROTOPLANETARY DISK SYSTEMS. II. CARBON MONOXIDE FOURTH POSITIVE EMISSION AND ABSORPTION*
Authors: France Kevin , Schindhelm Rebecca N. , Burgh Eric B. , Herczeg Gregory J. , Harper Graham M. , Brown Alexander , Green James C. , Linsky Jeffrey L. , Yang Hao , Abgrall Hervé , Ardila David R. , Bergin Edwin , Bethell Thomas , Brown Joanna M. , Calvet Nuria , Espaillat Catherine , Gregory Scott G. , Hillenbrand Lynne A. , Hussain Gaitee , Ingleby Laura , Johns-Krull Christopher M. , Roueff Evelyne , Valenti Jeff A. , Walter Frederick M.
Published: May 2011

We exploit the high sensitivity and moderate spectral resolution of the Hubble Space Telescope Cosmic Origins Spectrograph to detect far-ultraviolet (UV) spectral features of carbon monoxide (CO) present in the inner regions of protoplanetary disks for the first time. We present spectra of the classical T Tauri stars HN Tau, RECX-11, and V4046 Sgr, representative of a range of CO radiative processes. HN Tau shows CO bands in absorption against the accretion continuum. The CO absorption most likely arises in warm inner disk gas. We measure a CO column density and rotational excitation temperature of N(CO) = (2 ± 1) × 1017 cm−2 and T
rot(CO) 500 ± 200 K for the absorbing gas. We also detect CO A–X band emission in RECX-11 and V4046 Sgr, excited by UV line photons, predominantly H i Lyα. All three objects show emission from CO bands at λ > 1560 Å, which may be excited by a combination of UV photons and collisions with non-thermal electrons. In previous observations these emission processes were not accounted for due to blending with emission from the accretion shock, collisionally excited H2, and photo-excited H2, all of which appeared as a “continuum” whose components could not be separated. The CO emission spectrum is strongly dependent upon the shape of the incident stellar Lyα emission profile. We find CO parameters in the range: N(CO) ∼ 1018–1019 cm−2, T
rot(CO) ≳ 300 K for the Lyα-pumped emission. We combine these results with recent work on photo-excited and collisionally excited H2 emission, concluding that the observations of UV-emitting CO and H2 are consistent with a common spatial origin. We suggest that the CO/H2 ratio (≡ N(CO)/N(H2)) in the inner disk is ∼1, a transition between the much lower interstellar value and the higher value observed in solar system comets today, a result that will require future observational and theoretical study to confirm.
Squeeze effect and coherent coupling behaviour in photonic crystal vertical-cavity surface-emitting lasers
Authors: Liu An-Jin , Chen Wei , Zhou Wen-Jun , Jiang Bin , Fu Feiya , Qu Hong-Wei , Zheng Wan-Hua
Published: May 2011

The caption of figure 11 should be changed from:

Figure 11.Spectrum of device B at currents of (a) 0 mA and (b) 30 mA. The inset in (b) is the magnified spectrum.

to:

Figure 11.(a) Spectrum measured from figure 10(b) for device B. (b) Spectrum of light emitting out from the central defect of device B at 30 mA. The inset is the magnified spectrum.
Empirical likelihood for small area estimation
Authors: Chaudhuri Sanjay , Ghosh Malay
Published: May 2011

Current methodologies in small area estimation are mostly either parametric or heavily dependent on the assumed linearity of the estimators of the small area means. We discuss an alternative empirical likelihood-based Bayesian approach, which neither requires a parametric likelihood nor assumes linearity of the estimators, and can handle both discrete and continuous data in a unified manner. Empirical likelihoods for both area- and unit-level models are introduced. We discuss the suitability of the proposed likelihoods in Bayesian inference and illustrate their performances on a real dataset and a simulation study.
Epidemiology
Authors: Smith Blair H. , Torrance Nicola
Published: May 2011

Lack of agreed definitions and diagnostic criteria for neuropathic pain hamper epidemiological studies.

Neuropathic pain is likely to become more common in future because of ageing populations and improved recognition.

Neuropathic pain probably affects around 8% of UK adults, around 24% or more of patients with long-standing diabetes, and around 20% of those who have had shingles....
Screening tools and measurement tools for neuropathic pain
Authors: Bennett Michael I.
Published: May 2011

Verbal description differs between neuropathic and nociceptive pain and can contribute important information to the assessment process

Screening tools alert the clinician to the possible presence of neuropathic pain mechanisms but they do not replace clinical diagnosis

Measurement tools assess the intensity of particular qualities of neuropathic pain once a diagnosis has been made...
Peripheral neuropathic pain
Authors: Nash Tim
Published: May 2011

Damage to peripheral nerves, including cranial nerves and spinal nerve roots, can result in peripheral neuropathic pain

Speed of onset and associated symptoms and signs can point towards possible causes

Common conditions include diabetic neuropathy, post-herpetic neuralgia, and post-surgical neuropathies including phantom limb pain

Less common conditions result from Guillain-Barr syndrome, deficiency states, and toxic neuropathies...
Local anaesthetics and other pharmacological approaches
Authors: McCleane Gary
Published: May 2011

While antidepressants, antiepileptics, and opioids form the mainstay of neuropathic pain management, alternative approaches are needed because not all patients respond to these drugs and side-effects can limit their use in others

Topically applied drugs such a lidocaine 5% patches and capsaicin cream can produce local analgesic effects, though lidocaine is better tolerated...
Intrathecal drug delivery and neurolytic blocks
Authors: Simpson Karen H. , Jones Iain
Published: May 2011

Intrathecal drug delivery (ITDD) allows drugs to be placed near to central receptors

Drug side-effects may be reduced as small doses are required compared to with systemic administration

External or internal ITDD systems are available

ITDD requires careful patient selection and preparation

Opioids, local anaesthetics, and clonidine are the most commonly used intrathecal drugs; ziconotide can be used as first line treatment...
Incidental CD8 T cell reactivity against caspase-cleaved apoptotic self-antigens from ubiquitously expressed proteins in islets from prediabetic human leucocyte antigen-A2 transgenic non-obese diabetic mice
Authors: Coppieters K T , Amirian N , von Herrath M G
Published: May 2011

Apoptosis is known as a major mechanism which contributes to beta cell decay in type 1 diabetes. Commitment to this pathway generally involves caspase-mediated protein cleavage and was found to induce cross-presentation of a specific antigen repertoire under certain inflammatory conditions. We aimed to assess the significance of the CD8 T cell population reactive against such caspase-cleaved apoptotic self-antigens in pancreatic islets of prediabetic human leucocyte antigen (HLA)-A2 transgenic non-obese diabetic chimeric monochain transgene construct (NOD.HHD) mice. We have reproduced a unique peptide library consisting of human CD8 T cell-derived apoptosis-specific antigens, all of which belong to structural proteins expressed ubiquitously in human islets. Pancreatic islets from prediabetic NOD.HHD mice, harbouring humanized major histocompatibilty complex (MHC) class I, were isolated and handpicked at various ages, and islet-infiltrating CD8 T cells were expanded in vitro and used as responders in an interferon (IFN)-γ enzyme-linked immunospot (ELISPOT) assay. Human T2 cells were used as antigen-presenting cells (APC) to avoid endogenous antigen presentation. Analogous to the interindividual variability found with peptides from known islet autoantigens such as islet-specific glucose-6-phosphatase catalytic subunit related protein (IGRP) and insulin, some mice showed variable, low-degree CD8 T cell reactivity against caspase-cleaved self-antigens. Because reactivity was predominantly minor and often undetectable, we conclude that beta cell apoptosis does not routinely provoke the development of dominant cytotoxic T lymphocyte (CTL) reactive against caspase-cleaved self-antigens in the NOD.HHD model.
The biological hallmarks of ileal carcinoids
Authors: Cunningham Janet L. , Janson Eva T.
Published: May 2011

Eur J Clin Invest 2011; 41 (12): 1353–1360

Endocrine tumours derived from the small intestine, ileal carcinoids, produce and secrete the hormones tachykinins and serotonin, which induces the specific symptoms related to the tumour. Because of their low proliferation rate, they are often discovered at late stages when metastases have occurred. The biology that characterizes these tumours differs in many ways from what is generally recognized for other malignancies. In this overview, the current knowledge on the development and progression of ileal carcinoids is described.