bluuebunny/crossref_metadata_2025 huggingface dataset:
Cyclic GMP/protein kinase G type‐Iα (PKG‐Iα) signaling pathway promotes CREB phosphorylation and maintains higher c‐IAP1, livin, survivin, and Mcl‐1 expression and the inhibition of PKG‐Iα kinase activity synergizes with cisplatin in non‐small cell lung cancer cells
Authors: Wong Janica C. , Bathina Madhavi , Fiscus Ronald R.
Published: June 2012

Previously, our laboratory showed that nitric oxide (NO)/cyclic GMP (cGMP)/protein kinase G type‐Iα (PKG‐Iα) signaling pathway plays an important role in preventing spontaneous apoptosis and promoting cell proliferation in both normal cells (bone marrow stromal cells and vascular smooth muscle cells) and certain cancer cells (ovarian cancer cells). In the present study, we investigated the novel role of the cGMP/PKG‐Iα pathway in preventing spontaneous apoptosis, promoting colony formation and regulating phosphorylation of cAMP response element binding (CREB) protein and protein expression of inhibitor of apoptosis proteins (IAPs) and anti‐apoptotic Bcl‐2‐related proteins in NCI‐H460 and A549 non‐small cell lung cancer (NSCLC) cells. 1H‐(1,2,4)oxadiazolo(4,3‐a)quinoxalin‐1‐one (ODQ), which blocks endogenous NO‐induced activation of cGMP/PKG‐Iα, induced apoptosis and decreased colony formation. ODQ also decreased CREB ser133 phosphorylation and protein expression of c‐IAP1, livin, and survivin. DT‐2 (inhibitor of PKG‐Iα kinase activity) increased apoptosis by twofold and decreased CREB ser133 phosphorylation and c‐IAP1, livin, and survivin expression. Gene knockdown of PKG‐Iα expression using small‐interfering RNA increased apoptosis and decreased CREB ser133 phosphorylation, and c‐IAP1, livin, survivin, and Mcl‐1 expression. Inhibition of PKG‐Iα kinase activity with DT‐2 dramatically enhanced pro‐apoptotic effects of the chemotherapeutic agent cisplatin. Combined treatment of DT‐2 and cisplatin increased apoptosis compared with cisplatin or DT‐2 alone, showing a synergistic effect. The data suggest that the PKG‐Iα kinase activity is necessary for maintaining higher levels of CREB phosphorylation at ser133 and protein expression of c‐IAP1, livin, survivin, and Mcl‐1, preventing spontaneous apoptosis and promoting colony formation in NSCLC cells, which may limit the effectiveness of chemotherapeutic agents like cisplatin. J. Cell. Biochem. 113: 3587–3598, 2012. © 2012 Wiley Periodicals, Inc.
Nitric oxide enhanced reduction in a rotating drum biofilter coupled with absorption by FeII(EDTA)
Authors: Chen Jun , Dai Qi‐zhou , Qian Hai‐feng , Jiang Yi‐feng , Chen Jianmeng
Published: June 2012

BACKGROUND: The ongoing emission of nitric oxide (NO) is a serious persistent environmental problem, because it contributes to atmospheric ozone destruction and global warming. A novel and effective system was developed for the complete treatment of NO from flue gases. The system features NO absorption by FeII(EDTA) and biological denitrification in a rotating drum biofilter (RDB).

RESULTS: After 100 mg L−1 FeII(EDTA) was added to the nutrient solution, the results show that the NO removal efficiency was improved from 70.56% to 80.15%, the optimal temperature improved from 32.5 °C to 40.5 °C, and the pH improved from 7.5 to 8.0–8.3. A maximum NO removal efficiency of 96.5% was achieved when 500 mg L−1 FeII(EDTA) was used in the nutrient solution.

CONCLUSION: This experiment demonstrates that FeII(EDTA) could not only improve the mass transfer efficiency of NO from gas to liquid, but also serve as an electron donor for the biological reduction of NO to N2. The new integrated treatment system seemed to be a promising alternative for the complete treatment of NO from flue gases. © 2012 Society of Chemical Industry
Characterization of sodium cellulose sulphate/poly‐dimethyl‐diallyl‐ammonium chloride biological capsules for immobilized cultivation of microalgae
Authors: Zeng Xianhai , Danquah Michael K. , Potumarthi Ravichandra , Cao Jia , Chen Xiao Dong , Lu Yinghua
Published: June 2012

BACKGROUND: Microalgae continue to be a focus of industrial bioprocess sustainability practice owing to the numerous biofuels and bioproducts that can be obtained with simultaneous environmental bioremediation applications. However, the extremely dilute nature of large volume microalgal cultures and the small particle size of single‐cell microalgae present technological and economic problems of effective dewatering, thus affecting the application of microalgae in process industries. Microalgae immobilization using biocompatible polymeric systems has proved to be an effective strategy to circumvent the heavy dewatering requirement, as this approach provides physical separation between the solid microalgal cells and the liquid medium.

RESULTS: In this work, a novel microalgae immobilization carrier, sodium cellulose sulphate/poly‐dimethyl‐diallyl‐ammonium chloride (NaCS‐PDMDAAC) capsule, was synthesized and the resulting polymeric capsules were characterized using physicochemical techniques such as Fourier transform infrared spectroscopy (FT‐IR), scanning electron microscopy equipped with energy dispersive X‐ray spectroscopy (SEM‐EDX) and nuclear magnetic resonance spectroscopy (NMR). Experimental results showed that the unique properties of NaCS‐PDMDAAC capsules, such as pore size, capsule size, mechanical strength, and structural and compositional homogeneity, relevant to microalgae cultivation with batch or continuous nutrient removal can be accurately controlled.

CONCLUSION: These polymeric capsules find applications not only with microalgae cultivation but also for other microorganisms. © 2012 Society of Chemical Industry
Feedback Vertex Sets in Tournaments
Authors: Gaspers Serge , Mnich Matthias
Published: June 2012

We study combinatorial and algorithmic questions around minimal feedback vertex sets (FVS) in tournament graphs. On the combinatorial side, we derive upper and lower bounds on the maximum number of minimal FVSs in an n‐vertex tournament. We prove that every tournament on n vertices has at most 1.6740n minimal FVSs, and that there is an infinite family of tournaments, all having at least 1.5448n minimal FVSs. This improves and extends the bounds of Moon (1971). On the algorithmic side, we design the first polynomial space algorithm that enumerates the minimal FVSs of a tournament with polynomial delay. The combination of our results yields the fastest known algorithm for finding a minimum‐sized FVS in a tournament.
Binding Number, Minimum Degree, and Cycle Structure in Graphs
Authors: Bauer D. , Schmeichel E.
Published: June 2012

A well‐known theorem of Woodall states that if a graph G has binding number at least 3/2, then G is hamiltonian. We generalize Woodall's theorem as follows.
A practical radiosynthesis of a tritium‐labelled fluorocombretastatin
Authors: Hadfield John A. , Hirst Nicholas , Gaukroger Keira , Lawrence Nicholas J. , McGown Alan T.
Published: June 2012

Zybrestat (combretastatin A‐4 disodium diphosphate) is currently in clinical trials as an antivascular anticancer agent. A similar fluorinated agent has shown promise as an antivascular agent, and a radiolabelled version would enable further understanding of its biological activities. Herein is described the synthesis of a tritiated fluorinated analogue of Zybrestat. Copyright © 2012 John Wiley & Sons, Ltd.
Cardiovascular effects of the microinjection of L‐proline into the third ventricle or the paraventricular nucleus of the hypothalamus in unanesthetized rats
Authors: Lopes‐Azevedo Silvana , Scopinho América Augusto , Busnardo Cristiane , Aguiar Corrêa Fernando Morgan
Published: June 2012

We investigated the cardiovascular effects of the microinjection of L‐proline (L‐Pro) into the third ventricle (3V) and its peripheral mechanisms. Different doses of L‐Pro into the 3V caused dose‐related pressor and bradycardiac responses. The pressor response to L‐Pro injected into the 3V was potentiated by intravenous pretreatment with the ganglion blocker pentolinium (5 mg/kg), thus excluding any significant involvement of the sympathetic nervous system. Because the response to the microinjection of L‐Pro into the 3V was blocked by intravenous pretreatment with the V1‐vasopressin receptor antagonist dTyr(CH2)5(Me)AVP (50μg/kg), it is suggested that these cardiovascular responses are mediated by a vasopressin release. The pressor response to the microinjection of L‐Pro into the 3V was found to be mediated by circulating vasopressin, so, given that the paraventricular nucleus of the hypothalamus (PVN) is readily accessible from the 3V, we investigated whether the PVN could be a site of action for the L‐Pro microinjected in the 3V. The microinjection of L‐Pro (0.033 μmoles/0.1 μl) into the PVN caused cardiovascular responses similar to those of injection of the 3V and were also shown to be mediated by vasopressin release. In conclusion, these results show that the microinjection of L‐Pro into the 3V causes pressor and bradycardiac responses that could involve stimulation of the magnocellular cells of the PVN and release of vasopressin into the systemic circulation. Also, because the microinjection of L‐Pro into the PVN caused a pressor response, this is the first evidence of cardiovascular effects caused by its injection in a supramedullary structure. © 2012 Wiley Periodicals, Inc.
Activity‐dependent energy budget for neocortical signaling: Effect of short‐term synaptic plasticity on the energy expended by spiking and synaptic activity
Authors: DiNuzzo Mauro , Giove Federico
Published: June 2012

The available estimate of the energy expended for signaling in rat neocortex is refined to examine the separate contribution of spiking and synaptic activity as a function of average neuronal firing rate. By taking into account a phenomenological model of short‐term synaptic plasticity, we show that the transition from low to high cortical activity is accompanied by a substantial increase in relative energy consumed by action potentials vs. synaptic potentials. This consideration might be important for a deeper understanding of how information is represented in the cortex and which metabolic pathways are upregulated to sustain cortical activity. © 2012 Wiley Periodicals, Inc.
Differential effects of distinct central nervous system regions on cell migration and axonal extension of neural precursor transplants
Authors: Jin Ying , Sura Karna , Fischer Itzhak
Published: June 2012

Transplantation of neural precursor cells (NPCs) is a promising therapeutic strategy in CNS injury. However, the adult CNS lacks instructive signals present during development and, depending on the region and type of transplant, may be inhibitory for neuron generation and axonal growth. We examined the effects of the white matter in different regions of the adult CNS on the properties of NPC transplants with respect to cell survival, differentiation, migration, and axonal growth. NPCs were prepared from day 13.5 embryonic spinal cord of transgenic rats that express the human placental alkaline phosphatase (AP) reporter. These NPCs were injected unilaterally into the cervical spinal cord white matter and into the corpus callosum of adult rats and were analyzed immunohistochemically 2 weeks later. NPCs survived in both regions and differentiated into astrocytes, oligodendrocytes, and neurons, with no apparent differences in survival or phenotypic composition. However, in the spinal cord white matter, graft‐derived cells, identified as precursors and glial cells, migrated from the injection site rostrally and caudally, whereas, in the corpus callosum, graft‐derived cells did not migrate and remained at the injection site. Importantly, graft‐derived neurons extended axons from the grafting site along the corpus callosum past the midline, entering into the contralateral side of the corpus callosum. These results demonstrate dramatic differences between white matter regions in the spinal cord and brain with respect to cell migration and axonal growth and underscore the importance of considering the effects of the local CNS environment in the design of effective transplantation strategies. © 2012 Wiley Periodicals, Inc.
LARGE‐WOOD LOADING FROM NATURAL AND ENGINEERED PROCESSES AT THE WATERSHED SCALE
Authors: Lawrence J. E. , Resh V. H. , Cover M. R.
Published: June 2012

Large wood, both live and dead, is essential for producing complex habitat in many streams, especially in forested watersheds that support salmonid populations. The addition of engineered wood structures is a common approach taken in many streams where past watershed management practices have resulted in reduced wood loading. We examined six 300‐m stream reaches in the Lagunitas Creek watershed, Northern California, to determine (i) the distribution of large wood in the bankfull channel and 10‐year floodplain, (ii) the influence of large wood on the size and distribution of pools and (iii) whether streams with engineered wood structures had greater diversity of pool habitat to support salmonid populations. We found that the amount of large wood in the bankfull channel and the amount available for recruitment from the 10‐year floodplain were highly variable among and within reaches examined and largely dependent on the local geomorphic setting. Stream reaches with engineered wood structures had elevated pool frequencies relative to reaches without these structures, suggesting a higher capacity to support salmonids during critical life stages. Among large wood pieces that had a strong influence on pool formation, 23% had an attached root wad and 66% were part of a cluster. All of the study reaches we examined had lower volumes of large wood in their bankfull channels than similar stream types with natural wood‐loading levels, suggesting that increased additions of large wood could provide ecosystem benefits over time. These principles can be understood and transferred effectively to other watersheds using a framework of wood‐loading process domains. Copyright © 2012 John Wiley & Sons, Ltd.
Analysis on the generalization of proxy signature
Authors: Tiwari Namita , Padhye Sahadeo
Published: June 2012

Proxy signature is a specific digital signature, which allows an original signer to delegate her signing capability to proxy signer and then, the later can perform message signing on behalf of the former. Authentication is a desired property in cryptographic protocols. The proxy signature provides this property. In this article, we cover the research progress made on proxy signature and investigate its relationships with other existing signature schemes having continuous progress until now. We also provide real‐world scenarios, to understand better the situations, where these schemes are applicable for security purposes. We analyze the security properties of existing schemes and make a comparison among them on the basis of different number theoretic problems. Some open problems are also discussed, to the best of our knowledge. In addition, we provide some future directions, which can be used as a hint to work further in the area of proxy signature. We hope that this article will provide a ready reference to work in the related area. Copyright © 2012 John Wiley & Sons, Ltd.
Bias and loss: the two sides of a biased coin
Authors: Atkinson Anthony C.
Published: June 2012

The paper assesses biased‐coin designs for sequential treatment allocation in clinical trials. Comparisons emphasise the importance of considering randomness, as well as treatment balance, which are calculated as bias and loss. In the numerical examples, the responses are assumed normally distributed, perhaps after transformation, and balance is required over a set of covariates. The effect of covariate distribution on the properties of five allocation rules is investigated, with an emphasis on methods of comparison, which also apply to other forms of response. The concept of admissibility shows that the widely used minimisation rule is outperformed by Atkinson's rule derived from the theory of optimum experimental design. We present a simplified form of this rule. For this rule, the ability to guess the next treatment allocation decreases with study size. For the other rules, it is constant. Copyright © 2012 John Wiley & Sons, Ltd.
Generalized multidimensional dynamic allocation method
Authors: Lebowitsch Jonathan , Ge Yan , Young Benjamin , Hu Feifang
Published: June 2012

Dynamic allocation has received considerable attention since it was first proposed in the 1970s as an alternative means of allocating treatments in clinical trials which helps to secure the balance of prognostic factors across treatment groups. The purpose of this paper is to present a generalized multidimensional dynamic allocation method that simultaneously balances treatment assignments at three key levels: within the overall study, within each level of each prognostic factor, and within each stratum, that is, combination of levels of different factors Further it offers capabilities for unbalanced and adaptive designs for trials. The treatment balancing performance of the proposed method is investigated through simulations which compare multidimensional dynamic allocation with traditional stratified block randomization and the Pocock–Simon method. On the basis of these results, we conclude that this generalized multidimensional dynamic allocation method is an improvement over conventional dynamic allocation methods and is flexible enough to be applied for most trial settings including Phases I, II and III trials. Copyright © 2012 John Wiley & Sons, Ltd.
Indicial lift response function: an empirical relation for finite‐thickness airfoils, and effects on aeroelastic simulations
Authors: Bergami Leonardo , Gaunaa Mac , Heinz Joachim
Published: June 2012

The aeroelastic response of wind turbines is often simulated in the time domain by using indicial response techniques. Unsteady aerodynamics in attached flow are usually based on Jones's approximation of the flat plate indicial response, although the response for finite‐thickness airfoils differs from the flat plate one.

The indicial lift response of finite‐thickness airfoils is simulated with a panel code, and an empirical relation is outlined connecting the airfoil indicial response to its geometric characteristics. The effects of different indicial approximations are evaluated on a 2D profile undergoing harmonic pitching motion in the attached flow region; the resulting lift forces are compared with computational fluid dynamics (CFD) simulations. The relevance for aeroelastic simulations of a wind turbine is also evaluated, and the effects are quantified in terms of variations of equivalent fatigue loads, ultimate loads, and stability limits.

The agreement with CFD computations of a 2D profile in harmonic motion is improved by the indicial function accounting for the finite‐thickness of the airfoil. Concerning the full wind turbine aeroelastic behavior, the differences between simulations on the basis of Jones's and finite‐thickness indicial response functions are rather small; Jones's flat‐plate approximation results in only slightly larger fatigue and ultimate loads, and lower stability limits. Copyright © 2012 John Wiley & Sons, Ltd.
Fatigue distribution optimization for offshore wind farms using intelligent agent control
Authors: Zhao Rongyong , Shen Wenzhong , Knudsen Torben , Bak Thomas
Published: June 2012

A novel control approach is proposed to optimize the fatigue distribution of wind turbines in a large‐scale offshore wind farm on the basis of an intelligent agent theory. In this approach, each wind turbine is considered to be an intelligent agent. The turbine at the farm boundary communicates with its neighbouring downwind turbines and organizes them adaptively into a wind delivery group along the wind direction. The agent attributes and the event structure are designed on the basis of the intelligent agent theory by using the unified modelling language. The control strategy of the intelligent agent is studied using topology models. The reference power of an individual wind turbine from the wind farm controller is re‐dispatched to balance the turbine fatigue in the power dispatch intervals. In the fatigue optimization, the goal function is to minimize the standard deviation of the fatigue coefficient for every wind turbine. The optimization is constrained such that the average fatigue for every turbine is smaller than what would be achieved by conventional dispatch and such that the total power loss of the wind farm is restricted to a few percent of the total power. This intelligent agent control approach is verified through the simulation of wind data from the Horns Rev offshore wind farm. The results illustrate that intelligent agent control is a feasible way to optimize fatigue distribution in wind farms, which may reduce the maintenance frequency and extend the service life of large‐scale wind farms. Copyright © 2012 John Wiley & Sons, Ltd.
Has the situation of the ‘have‐nots’ improved?
Authors: Jannuzzi Gilberto De Martino , Goldemberg José
Published: June 2012

The need to promote significant changes in the production and use of energy in the direction of cleaner fuels and greater energy efficiency provide opportunities to reduce this gap of energy consumption indices between the rich and poor, both in developing and developed countries. Wide disparities in the access and consumption levels of modern fuels and electricity still persist between developing and developed countries, in spite of increased international awareness and efforts. This paper shows that progress has been made in order to increase access to electricity and cleaner cooking fuels and this has improved the standards of living of poor population. However, more efforts are necessary in order to speed up the reduction of the energy gap and eliminate energy poverty. Greater investments in energy efficiency are an essential part of this strategy and some countries are pursuing it.

This article is categorized under:

Energy Policy and Planning > Economics and Policy

Energy and Development > Climate and Environment
New Rare‐Earth Metal Germanides RE2Ge9 (RE = Nd, Sm) by Thermal Decomposition of High‐Pressure Phases REGe5
Authors: Meier Katrin , Wosylus Aron , Cardoso‐Gil Raul , Burkhardt Ulrich , Curfs Caroline , Hanfland Michael , Grin Yuri , Schwarz Ulrich
Published: June 2012

The rare‐earth metal germanides RE2Ge9 (RE = Nd, Sm) have been prepared by thermal decomposition of the metastable high‐pressure phases REGe5 at ambient pressure. The compounds adopt an orthorhombic unit cell with a = 396.34(4) pm; b = 954.05(8) pm and c = 1238.4(1) pm for Nd2Ge9 and a = 395.46(7) pm; b = 946.4(2) pm and c = 1232.1(3) pm for Sm2Ge9. Crystal structure refinements reveal space group Pmmn (No. 59) for Nd2Ge9. The atomic pattern resembles an ordered defect variety of the pentagermanide motif REGe5 (RE = La; Nd, Sm, Gd, Tb) comprising corrugated germanium layers. These condense into a three‐dimensional network interconnected by eight‐coordinated germanium atoms. The resulting framework channels along [100] enclose the neodymium atoms. With respect to the atomic arrangement of the pentagermanides, half of the interlayer germanium atoms are eliminated in an ordered way so that occupied and empty germanium columns alternate along [001]. The rare‐earth metal atoms of both types of compounds, REGe5 and RE2Ge9, exhibit the electronic states 4f 3 and 4f 5 (oxidation state +3) for neodymium and samarium, respectively, evidencing that the modification of the germanium network leaves the electron configuration of the metal atoms unaffected.
A College of Nations: What Can Europeans and Americans Learn from Each Other?
Authors: Hill Steven
Published: June 2012

The transatlantic relationship has been the most important of the post–Second World War era, a relationship in which both sides have shared and learned many things. In this new era of post–economic collapse, Europeans and Americans still have much to learn from each other. This article focuses on a few key areas where Americans can learn from Europeans, including health care and family support, the economy, environmental sustainability, and political and economic democracy. Then the article briefly outlines some areas where Europeans can learn from Americans, specifically racial integration and forging a political and economic union.
Amadori‐glycated phosphatidylethanolamine up‐regulates telomerase activity in PANC‐1 human pancreatic carcinoma cells
Authors: Eitsuka Takahiro , Nakagawa Kiyotaka , Ono Yuichi , Tatewaki Naoto , Nishida Hiroshi , Kurata Tadao , Shoji Naoki , Miyazawa Teruo
Published: June 2012

Several lines of experimental data have highlighted a key role of Amadori‐glycated phosphatidylethanolamine (Amadori‐PE) in the development of diabetic complications. Recent epidemiological studies suggest that diabetes mellitus could be a risk factor for some cancers. A characteristic of cancer cells is their immortal phenotype, and the enzyme telomerase contributes to the infinite replicative potential of cancer cells. The purpose of this study was to obtain new information about the effect of Amadori‐PE on the regulation of telomerase in PANC‐1 human pancreatic carcinoma cells. Amadori‐PE enhanced cellular telomerase in a time‐ and dose‐dependent manner by up‐regulating hTERT expression through induction of c‐myc. These results provide experimental evidence for a novel role of Amadori‐PE in linking diabetes and cancer.
Analysis of strong ionospheric scintillation events measured by means of GPS signals at low latitudes during disturbed conditions
Authors: Forte B.
Published: June 2012

Drifting structures characterized by inhomogeneities in the spatial electron density distribution at ionospheric heights cause the scintillation of radio waves propagating through. The fractional electron density fluctuations and the corresponding scintillation levels may reach extreme values at low latitudes during high solar activity. Different levels of scintillation were observed on experimental data collected in the Asian sector at low latitudes by means of a GPS dual frequency receiver under moderate solar activity (2005). The GPS receiver used in these campaigns was particularly modified in firmware in order to record power estimates on the C/A code as well as on the carriers L1 and L2. Strong scintillation activity was recorded in the post‐sunset period (saturatingS4 and SI as high as 20 dB). Spectral modifications and broadening was observed during high levels of scintillation possibly indicating refractive scattering taking place instead of diffractive scattering. A possible interpretation of those events was attempted on the basis of the refractive scattering theory developed by Uscinski (1968) and Booker and MajidiAhi (1981).
Advancing hydroacoustic technologies for sedimentology research and monitoring
Authors: Landers Mark , Arrigo Jennifer , Gray John R.
Published: June 2012

Joint USGS‐CUAHSI Workshop on Sediment Hydroacoustic Techniquesfor Rivers and Streams; Shepherdstown, West Virginia, 20–22 March 2012
Towards a universal criteria for turbulence suppression in dilute turbidity currents with non‐cohesive sediments
Authors: Cantero Mariano I. , Shringarpure Mrugesh , Balachandar S.
Published: June 2012

Turbidity currents exhibit fascinating physics as their sustained propagation depends on a tight interplay between the suspended sediments and turbulence. If resuspension dominates over deposition the intensity of the flow will increase, while if deposition dominates the flow turbulence can be completely damped inducing rapid settling of sediments and, eventually, flow extinction. This work explores the phenomenon whereby turbulence in a dilute turbidity current with non‐cohesive sediments is abruptly extinguished owing to increased suspended sediment stratification. Three parameters control the flow dynamics: Reynolds number (Reτ), Richardson number (Riτ) and sediment settling velocity (
). The condition for complete turbulence suppression can be expressed as a critical value for
. Based on simulations, limited experiments and limited field data, the critical value appears to have a logarithmic dependence on Reτ.
Projected changes in water availability in the United Kingdom
Authors: Sanderson Michael G. , Wiltshire Andrew J. , Betts Richard A.
Published: June 2012

There is evidence for a change in the seasonality of UK rainfall consistent with projections from climate models, which could have a significant impact on water availability. This paper describes an analysis of seasonal mean runoff in the UK calculated directly within an ensemble of regional climate models. Both surface and subsurface runoff have been analyzed, and the times at which a climate change signal in the runoff could be detected have also been calculated. Runoff is projected to increase in winter in all regions of the UK, by 5–25% by the 2080s, but remain the same or decrease in the other seasons. We find that a climate change signal could be detected in runoff in winter in western parts of the UK as early as the 2020s, but much later in eastern areas of England. In summer, detection times (2040–2060 s) are generally later than those in winter (2020–2040 s). Our results imply water resources in the southeast of the UK could be reduced during the twenty‐first century, and adaptation may be needed long before a formal detection of a climate change signal is made.
A comparative experimental and multiphysics computational fluid dynamics study of coupled surface–subsurface flow in bed forms
Authors: Janssen Felix , Cardenas M. Bayani , Sawyer Audrey H. , Dammrich Thea , Krietsch Jana , de Beer Dirk
Published: June 2012

The use of multiphysics computational fluid dynamics (CFD) approaches to simulate surface–subsurface flow processes is evaluated by comparison with flume experiments on current‐exposed permeable bed forms. The unique experimental data include measurements of the time‐averaged surface water flow velocities, the pressure distribution at the sediment–water interface, and pore water flow paths. The modeling approach first simulates the time‐averaged turbulent flow in the channel with CFD and then uses the predicted pressure distribution at the sediment–water interface to drive a flow and transport model for the sediment. The CFD‐modeled velocity and pressure distribution and transient particle tracks within the sediment agree reasonably well with observations. Differences that exist between observations and simulations mainly concern the eddies in the wake zone downstream of the ripple crests that are slightly shorter than those predicted by the model. This deviation propagates from the surface to the subsurface domain, appearing in the pressure distribution along the bed and, consequently, the subsurface flow patterns. The good representation of general patterns and rates makes multiphysics CFD modeling a powerful and sufficiently accurate tool that can replace measurements for many studies of surface–subsurface processes involving current‐exposed immobile bed forms. The approach can be used for predicting transport processes where they cannot easily be observed, such as in large rivers and coastal systems where boundary conditions such as mean currents and bed forms can be mapped.
Effect of Hypoxia and Hyperoxia on Cerebral Blood Flow, Blood Oxygenation, and Oxidative Metabolism
Authors: Xu Feng , Liu Peiying , Pascual Juan M , Xiao Guanghua , Lu Hanzhang
Published: June 2012

Characterizing the effect of oxygen (O2) modulation on the brain may provide a better understanding of several clinically relevant problems, including acute mountain sickness and hyperoxic therapy in patients with traumatic brain injury or ischemia. Quantifying the O2 effects on brain metabolism is also critical when using this physiologic maneuver to calibrate functional magnetic resonance imaging (fMRI) signals. Although intuitively crucial, the question of whether the brain's metabolic rate depends on the amount of O2 available has not been addressed in detail previously. This can be largely attributed to the scarcity and complexity of measurement techniques. Recently, we have developed an MR method that provides a noninvasive (devoid of exogenous agents), rapid (<5 minutes), and reliable (coefficient of variant, CoV <3%) measurement of the global cerebral metabolic rate of O2 (CMRO2). In the present study, we evaluated metabolic and vascular responses to manipulation of the fraction of inspired O2 (FiO2). Hypoxia with 14% FiO2 was found to increase both CMRO2 (5.0±2.0%, N=16, P=0.02) and cerebral blood flow (CBF) (9.8±2.3%, P<0.001). However, hyperoxia decreased CMRO2 by 10.3±1.5% ( P<0.001) and 16.9±2.7% ( P<0.001) for FiO2 of 50% and 98%, respectively. The CBF showed minimal changes with hyperoxia. Our results suggest that modulation of inspired O2 alters brain metabolism in a dose-dependent manner.
Characterization of cytoskeletal protein 4.1R interaction with NHE1 (Na+/H+ exchanger isoform 1)
Authors: Nunomura Wataru , Denker Sheryl P. , Barber Diane L. , Takakuwa Yuichi , Gascard Philippe
Published: June 2012

NHE1 (Na+/H+ exchanger isoform 1) has been reported to be hyperactive in 4.1R-null erythrocytes [Rivera, De Franceschi, Peters, Gascard, Mohandas and Brugnara (2006) Am. J. Physiol. Cell Physiol. 291, C880–C886], supporting a functional interaction between NHE1 and 4.1R. In the present paper we demonstrate that 4.1R binds directly to the NHE1cd (cytoplasmic domain of NHE1) through the interaction of an EED motif in the 4.1R FERM (4.1/ezrin/radixin/moesin) domain with two clusters of basic amino acids in the NHE1cd, K519R and R556FNKKYVKK, previously shown to mediate PIP2 (phosphatidylinositol 4,5-bisphosphate) binding [Aharonovitz, Zaun, Balla, York, Orlowski and Grinstein (2000) J. Cell. Biol. 150, 213–224]. The affinity of this interaction (Kd=100–200 nM) is reduced in hypertonic and acidic conditions, demonstrating that this interaction is of an electrostatic nature. The binding affinity is also reduced upon binding of Ca2+/CaM (Ca2+-saturated calmodulin) to the 4.1R FERM domain. We propose that 4.1R regulates NHE1 activity through a direct protein–protein interaction that can be modulated by intracellular pH and Na+ and Ca2+ concentrations.
Renin–angiotensin system blockade: a novel therapeutic approach in chronic obstructive pulmonary disease
Authors: Shrikrishna Dinesh , Astin Ronan , Kemp Paul R. , Hopkinson Nicholas S.
Published: June 2012

ACE (angiotensin-converting enzyme) inhibitors and ARBs (angiotensin II receptor blockers) are already widely used for the treatment and prevention of cardiovascular disease and their potential role in other disease states has become increasingly recognized. COPD (chronic obstructive pulmonary disease) is characterized by pathological inflammatory processes involving the lung parenchyma, airways and vascular bed. The aim of the present review is to outline the role of the RAS (renin–angiotensin system) in the pathogenesis of COPD, including reference to results from fibrotic lung conditions and pulmonary hypertension. The review will, in particular, address the emerging evidence that ACE inhibition could have a beneficial effect on skeletal muscle function and cardiovascular co-morbidity in COPD patients. The evidence to support the effect of RAS blockade as a novel therapeutic approach in COPD will be discussed.
Decay of energy and suppression of Fermi acceleration in a dissipative driven stadium-like billiard
Authors: Livorati André L. P. , Caldas Iberê L. , Leonel Edson D.
Published: June 2012

The behavior of the average energy for an ensemble of non-interacting particles is studied using scaling arguments in a dissipative time-dependent stadium-like billiard. The dynamics of the system is described by a four dimensional nonlinear mapping. The dissipation is introduced via inelastic collisions between the particles and the moving boundary. For different combinations of initial velocities and damping coefficients, the long time dynamics of the particles leads them to reach different states of final energy and to visit different attractors, which change as the dissipation is varied. The decay of the average energy of the particles, which is observed for a large range of restitution coefficients and different initial velocities, is described using scaling arguments. Since this system exhibits unlimited energy growth in the absence of dissipation, our results for the dissipative case give support to the principle that Fermi acceleration seems not to be a robust phenomenon.
Prediction of the existence of the N2H− molecular anion
Authors: Lique François , Halvick Philippe , Stoecklin Thierry , Hochlaf Majdi
Published: June 2012

We predict the existence of the N2H− anion from first principle calculations. We present the three-dimensional potential energy surface and the bound states of the N2H−/D− van der Waals anion. The electronic calculations were performed using state-of-the-art ab initio methods and the nuclear motions were solved using a quantum close-coupling scattering theory. A T-shaped equilibrium structure was found, with a well depth of 349.1 cm−1, where 18 bound states have been located for N2H− and 25 for N2D− for total angular momentum J = 0. We also present the absorption spectra of the N2H− complex. This anion could be formed after low energy collisions between N2 and H− through radiative association. The importance of this prediction in astrophysics and the possible use of N2H− as a tracer of N2 and H− in the interstellar medium is discussed.
Ultraviolet emission efficiency enhancement of a-plane AlGaN/GaN multiple-quantum-wells with increasing quantum well thickness
Authors: Huang Huei-Min , Chang Chiao-Yun , Lan Yu-Pin , Lu Tien-Chang , Kuo Hao-Chung , Wang Shing-Chung
Published: June 2012

The defect-induced carrier localization in nonpolar a-plane (Al,Ga)N/GaN multiple quantum wells (MQWs) structures with different well thickness have been investigated. A strong variation of temperature-dependent photoluminescence peak energy was observed and attributed to the existence of the localized states. The degree of carrier localization in these defect-induced states was more prominent in the case of MQWs with the wider well width. In addition, the ultraviolet light emission efficiency revealed a 3-fold enhancement with increasing the well width from 1.6 nm to 7.3 nm, due to the strong carrier localization generated from the quantum-wire-like features formed by the intersection between basal stacking faults and quantum wells.
Charged exciton creation with two-color optical excitation method and analysis of initialization process of electron spin qubit in quantum dots
Authors: Gotoh Hideki , Sanada Haruki , Yamaguchi Hiroshi , Sogawa Tetsuomi
Published: June 2012

An optical pumping method for creating charged excitons in semiconductor quantum dots is studied using a micro-photoluminescence (PL) technique with a two-color excitation method. This method employs two laser sources whose energies are in the resonant and non-resonant barrier excitation conditions, respectively; one laser creates excitons, the other creates electrons. The two-color excitation exploits an asymmetric energy band structure for conduction and valence bands, which induces negatively charged excitons in single quantum dots. The PL spectra of a single quantum dot clearly vary from exciton-originated PL to charged exciton-originated PL as the excitation conditions are changed. This excitation method is applied to the initialization process of an electron spin qubit without a magnetic field. Experimental results are analyzed theoretically based on the use of a density matrix method for the initialization. The analysis reveals that the electron spin in quantum dots is sufficiently polarized for subsequent quantum computation processes. These results provide a simple and effective way of implementing quantum computing with spin qubits.
Fe3+ doping effects on the structure and multiferroicity of Fe1+xV2−xO4 (0 ≤ x ≤ 0.4) spinels
Authors: Liu N. , Zhao K. H. , Shi X. L. , Zhang L. W.
Published: June 2012

We studied the evolution of the structural, electric, magnetic, and multiferroic properties with x in Fe1+xV2−xO4 (0 ≤ x ≤ 0.4) spinels. For x = 0, three successive phase transitions occur from high to low temperatures: cubic-tetragonal (c < a) at TS, tetragonal (c < a) paramagnetic-orthorhombic ferrimagnetic at TN1, and orthorhombic collinear spin-tetragonal (c > a) noncollinear spin at TN2. Below TN2, magnetic field dependent ferroelectricity was observed. With increasing x from 0 to 0.3, TN1 was increased, while TS and TN2 was decreased with ferroelectricity weakened. For x = 0.4, TN2 together with ferroelectricity disappeared. The critical composition xc is around 0.3. Below xc, the resistivity follows the variable range hopping model, while above xc, the resistivity obeys nearest neighbor hooping model. Our observations evidence the strong couplings among the lattice, charge, orbital, and spin degrees of freedom as well as their effects on the structural, electric, magnetic and multiferroic properties in Fe1+xV2−xO4 spinels.
Special structures and properties of hydrogen nanowire confined in a single walled carbon nanotube at extreme high pressure
Authors: Xia Yueyuan , Zhao Mingwen , Liu Xiangdong , Song Chen , He Tao , Fang Jiaxiong
Published: June 2012

Extensive ab initio molecular dynamics simulations indicate that hydrogen can be confined in single walled carbon nanotubes to form high density and high pressure H2 molecular lattice, which has peculiar shell and axial structures depending on the density or pressure. The band gap of the confined H2 lattice is sensitive to the pressure. Heating the system at 2000K, the H2 lattice is firstly melted to form H2 molecular liquid, and then some of the H2 molecules dissociate accompanied by drastic molecular and atomic reactions, which have essential effect on the electronic structure of the hydrogen system. The liquid hydrogen system at 2000K is found to be a particular mixed liquid, which consists of H2 molecules, H atoms, and H-H-H trimers. The dissociated H atoms and the trimers in the liquid contribute resonance electron states at the Fermi energy to change the material properties substantially. Rapidly cooling the system from 2000K to 0.01 K, the mixed liquid is frozen to form a mixed solid melt with a clear trend of band gap closure. It indicates that this solid melt may become a superconducting nanowire when it is further compressed.
The Cognitive Neuroscience of Crossmodal Correspondences
Authors: Spence Charles , Parise Cesare V.
Published: June 2012

In a recent article, N. Bien, S. ten Oever, R. Goebel, and A. T. Sack (2012) used event-related potentials to investigate the consequences of crossmodal correspondences (the “natural” mapping of features, or dimensions, of experience across sensory modalities) on the time course of neural information processing. Then, by selectively lesioning the right intraparietal cortex using transcranial magnetic stimulation, these researchers went on to demonstrate (for the first time) that it is possible to temporarily eliminate the effect of crossmodal congruency on multisensory integration (specifically on the spatial ventriloquism effect). These results are especially exciting given the possibility that the cognitive neuroscience methodology utilized by Bien et al. (2012) holds for dissociating between putatively different kinds of crossmodal correspondence in future research.
Surface phonons, elastic response, and conformal invariance in twisted kagome lattices
Authors: Sun Kai , Souslov Anton , Mao Xiaoming , Lubensky T. C.
Published: June 2012

Model lattices consisting of balls connected by central-force springs provide much of our understanding of mechanical response and phonon structure of real materials. Their stability depends critically on their coordination number
z
.
d
-dimensional lattices with
z
 = 2
d
are at the threshold of mechanical stability and are isostatic. Lattices with
z
 < 2
d
exhibit zero-frequency “floppy” modes that provide avenues for lattice collapse. The physics of systems as diverse as architectural structures, network glasses, randomly packed spheres, and biopolymer networks is strongly influenced by a nearby isostatic lattice. We explore elasticity and phonons of a special class of two-dimensional isostatic lattices constructed by distorting the kagome lattice. We show that the phonon structure of these lattices, characterized by vanishing bulk moduli and thus negative Poisson ratios (equivalently, auxetic elasticity), depends sensitively on boundary conditions and on the nature of the kagome distortions. We construct lattices that under free boundary conditions exhibit surface floppy modes only or a combination of both surface and bulk floppy modes; and we show that bulk floppy modes present under free boundary conditions are also present under periodic boundary conditions but that surface modes are not. In the long-wavelength limit, the elastic theory of all these lattices is a conformally invariant field theory with holographic properties (characteristics of the bulk are encoded on the sample boundary), and the surface waves are Rayleigh waves. We discuss our results in relation to recent work on jammed systems. Our results highlight the importance of network architecture in determining floppy-mode structure.
Transient opening of the perineurial barrier for analgesic drug delivery
Authors: Hackel Dagmar , Krug Susanne M. , Sauer Reine-Solange , Mousa Shaaban A. , Böcker Alexander , Pflücke Diana , Wrede Esther-Johanna , Kistner Katrin , Hoffmann Tali , Niedermirtl Benedikt , Sommer Claudia , Bloch Laura , Huber Otmar , Blasig Ingolf E. , Amasheh Salah , Reeh Peter W. , Fromm Michael , Brack Alexander , Rittner Heike L.
Published: June 2012

Selective targeting of sensory or nociceptive neurons in peripheral nerves remains a clinically desirable goal. Delivery of promising analgesic drugs is often impeded by the perineurium, which functions as a diffusion barrier attributable to tight junctions. We used perineurial injection of hypertonic saline as a tool to open the perineurial barrier transiently in rats and elucidated the molecular action principle in mechanistic detail: Hypertonic saline acts via metalloproteinase 9 (MMP9). The noncatalytic hemopexin domain of MMP9 binds to the low-density lipoprotein receptor-related protein-1, triggers phosphorylation of extracellular signal-regulated kinase 1/2, and induces down-regulation of the barrier-forming tight junction protein claudin-1. Perisciatic injection of any component of this pathway, including MMP9 hemopexin domain or claudin-1 siRNA, enables an opioid peptide ([D-Ala2,
N
-Me-Phe4,Gly5-ol]-enkephalin) and a selective sodium channel (NaV1.7)-blocking toxin (ProToxin-II) to exert antinociceptive effects without motor impairment. The latter, as well as the classic TTX, blocked compound action potentials in isolated nerves only after disruption of the perineurial barrier, which, in return, allowed endoneurally released calcitonin gene-related peptide to pass through the nerve sheaths. Our data establish the function and regulation of claudin-1 in the perineurium as the major sealing component, which could be modulated to facilitate drug delivery or, potentially, reseal the barrier under pathological conditions.