bluuebunny/crossref_metadata_2025 huggingface dataset:
Controlled trans‐stereospecific polymerization of isoprene with lanthanide(III) borohydride/dialkylmagnesium systems: The improvement of the activity and selectivity, kinetic studies, and mechanistic aspects
Authors: Terrier Michaël , Visseaux Marc , Chenal Thomas , Mortreux André
Published: May 2007

Neodymium trisborohydride, associated with MgR2 alkylating agents, affords an efficient initiator for the stereospecific polymerization of isoprene. This system presents good activity (150 kg of polyisoprene/mol of Nd/h; 95% yield in 2 h) and is trans‐stereospecific (up to 97.7%), and its polymerization shows a quasi‐living character. The molecular weights are controlled by the [Isoprene]/[Nd] ratio, with a polydispersity index lower than 1.6. A full study is presented here, including the influence of the nature of the alkylating reagent (MgR2), the solvent, the reaction temperature, the [MgR2]/[Nd] ratio, and the replacement of neodymium by other lanthanides. This work also includes a kinetic study of the system and a detailed NMR study of the microstructure of the trans‐polyisoprene obtained, providing mechanistic insights about the polymerization reaction. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2400–2409, 2007
A comparative DFT study of substrates and products of industrial enzyme nitrile hydratase
Authors: Peplowski Lukasz , Kubiak Karina , Zelek Slawomir , Nowak Wieslaw
Published: May 2007

Nitrile hydratase (NHase) is a metalloenzyme used in industrial biotechnology for a large scale production of common chemicals. NHases convert nitriles to the corresponding amides. Although the structures of some forms of NHases containing nonheme low spin Fe(III) or low spin noncorrinoid Co(III) are known, neither a catalytic mechanism nor the reasons of high selectivity towards aromatic ligands are recognized. Optimized geometries, molecular electrostatic potential maps and infrared spectra of commercially important aromatic substrates of the NHase (nicotinonitrile, o‐, m‐, p‐methylbenzonitrile) and the corresponding products (nicotinamide, o‐, m‐, p‐methylbenzamid) were investigated using the density functional theory method with the B3LYP functional and the 6‐31G(d,p) basis set. Calculated hypothetical intrinsic reaction paths indicate that benzimidic acids may be involved as intermediates. This study elucidates differences in the electronic properties of substrates and products of NHases, provides an insight into the molecular basis of the catalytic reaction and helps to explain varying enzymatic activities of microbial NHases. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Selectivity of Supercritical CO2 in the Fractionation of Hake Liver Oil Ethyl Esters
Authors: Jachmanián Iván , Margenat Lucía , Torres Ana I. , Grompone Maria A.
Published: May 2007

The solubility of different ethyl esters derivatized from hake liver oil in supercritical carbon dioxide was studied. A selectivity factor was used to determine optimal conditions to fractionate the ethyl ester mixture. A strong influence of solvent pressure and temperature was observed within 8.63–18.04 MPa and 40–70 °C. The lowest total solubility of the ethyl ester mixture was obtained when using supercritical carbon dioxide at the lowest density (the lowest pressure and the highest temperatures value tested). The highest discrimination against long‐chain polyunsaturated fatty acids (e.g. EPA and DHA) was also obtained at these above conditions. Conversely, higher solubility and lower selectivity were obtained when solvent density increased. Considering this inverse correlation between selectivity and solubility, a single‐step batch‐fractionation process was designed to increase the 22:6 ethyl ester content from an initial value of 17.5% in the starting material to 55% in the final extract.
Anomalous stress field and active breaching at relay ramps: a field example from Gediz Graben, SW Turkey
Authors: ÇİFTÇİ N. BOZKURT , BOZKURT ERDİN
Published: May 2007

Relay ramps form at different scales in extensional terrains to accommodate the differential stretching among the overlapping bounding-normal fault segments. The major boundary structure of the Gediz Graben (SW Turkey) is segmented, with formation, evolution and active breaching of relay ramps. The Akçapınar relay ramp is an example of these processes that forms within a 2 km wide overlap zone between ∼ E–W-trending segments on the southern margin of the Gediz Graben. Change of structural style at the ramp area is clearly evident from variations in the orientation of fractures and faults of the relay ramp. As a site of local stress field anomaly, ∼ N–S-trending structures in the Akçapınar relay ramp are conformable with the extension that is parallel to the bounding faults of the relay ramp. These structures are also superimposed onto the ∼ E–W-trending regional structural style by an obvious cross-cutting relationship, suggesting both spatial and temporal variation of the state of stress at the ramp area during the relay ramp formation. The regional stress field and the resulting regional structural style characterize the earlier stages of ramp evolution, during which segment interaction is limited. As segment interaction and relay ramp formation advances towards the breaching phase, an anomalous local stress field arises and the relay ramp area experiences extension parallel to the bounding normal faults, that is, transverse to the regional direction of extension. This creates a new structural style at the ramp area.
Primitive neuroectodermal tumour of the tongue
Authors: Gunawardena I , Kenwright D , Steventon N , Ferguson C
Published: May 2007

Peripheral primitive neuroectodermal tumours, which belong to the Ewing sarcoma tumour family, are extremely rare. These tumours are highly aggressive and are known to have a poor prognosis. Immunostaining with at least two neural markers and evidence of an abnormal t(11;22)(q24;q12) translocation are hallmark features in this diagnosis. We present the first reported case of peripheral primitive neuroectodermal tumour to occur in the tongue.
Cardiovascular hoarseness: an unusual presentation to otolaryngologists
Authors: Fennessy B G , Sheahan P , McShane D
Published: May 2007

Objective:

We discuss the case of a 73-year-old woman with a six-month history of hoarseness secondary to an aortic arch pseudoaneurysm.

Method:

We present the findings of an extensive review of the literature relating to cardiovascular disorders involving the recurrent laryngeal nerve (i.e. Ortner's syndrome).

Results:

Ortner's syndrome, also known as cardiovocal syndrome, is a rare condition, with few reports in the literature.

Conclusion:

This is only the second documented case of Ortner's syndrome in Great Britain and Ireland, and the first demonstrating an aortic pseudoaneurysm.
Dual pathology: cervicofacial actinomycosis and nicorandil-induced oral ulceration
Authors: Cupples H E V , McGahey D T
Published: May 2007

Introduction:

Oral ulceration has many causes and is a common presenting symptom in otolaryngology.

Case report:

This article presents an unusual case of dual pathology oral ulceration in an elderly patient. Oral malignancy was initially suspected, but the history, examination and investigation showed that the oral ulceration was caused by actinomycosis infection and by nicorandil use.

Discussion:

Cervicofacial acinomycosis is a rare, suppurative bacterial disease in which abscesses can form in the tissues and break through the skin, creating pus-discharging lesions. Nicorandil is a potassium channel blocker used in the treatment of ischaemic heart disease. It has been recently recognised as a cause of persistent ulcerative stomatitis.

Conclusion:

This case highlights the importance of a high index of suspicion for unusual and reversible causes of oral ulceration, and of dual pathology as a cause. Such vigilance enables early recognition and treatment of potentially reversible conditions.
Internal jugular vein thrombosis due to distant malignancies: two case reports and literature review
Authors: Pata Y S , Ünal M , Gülhan S
Published: May 2007

The internal jugular vein is an uncommon site of spontaneous venous thrombosis. Most cases usually result from intravenous drug abuse, jugular vein catheterisation, neck dissection, a hypercoagulable state associated with malignancy (Trousseau's syndrome), neck injury or ovarian overstimulation syndrome. In this paper, we present and discuss two cases of spontaneous jugular vein thrombosis associated with breast and lung malignancies. The possibility of Trousseau's syndrome due to distant malignancy should be considered by otolaryngologists and appropriately investigated.
The challenge of consensus building: Tanzania's PRSP 1998–2001
Authors: Holtom Duncan
Published: May 2007

As evidence of the failure of policy-based aid mounted in the early 1990s, a ‘new aid agenda’ developed. The agenda emphasised among other things, the importance of dialogue and partnership in order to help build ownership of more complex second-generation reforms. The Poverty Reduction Strategy Paper (PRSP) has developed as the key instrument for implementing this partnership in much of sub-Saharan Africa. However, this is not the only objective of the PRSP. Tanzania, at the forefront of attempts to restructure government–donor relations and one of the first countries to prepare a PRSP, illustrates the tensions created by the PRSP's complex genealogy and how these are being worked out in practice.
Youth, globalisation, and millennial reflection in a Guinean forest town
Authors: Straker Jay
Published: May 2007

The last two decades have witnessed a surge in studies of youth culture and social practice. In Africa, as elsewhere, this body of youth-centred research and writing has devoted considerable attention to specific groups within a given country's young population, while largely neglecting others seen to lack either culturally innovative or politically subversive traits. Youths in large cities and young combatants involved in insurgency or counter-insurgency have shared centre stage in studies of youthful Africa. This article argues for broadening the research agenda of African youth studies, calling for increased attention to the interpretive work performed by provincial youths as they try to understand and hopefully alter the future prospects of their communities in the new century. It shows how ideas about the meanings of globalisation and ‘the millennium’, intertwined with experiences of a recent refugee ‘crisis’, are shaping Guinean youths' socio-political reflections and yearnings. In doing so, it stresses just how complicated and cosmopolitan ‘provincial’ life, particularly for young people, has become in Guinea's forest region, as well as the variety and sophistication of the historical ‘materials’ and interpretive schemes through which these youths depict and judge possible local futures.
Call for papers: NJL Special Issue on the Syntax of Nominals and Noun Phrases
Authors: Delsing Lars-Olof
Published: May 2007

The second issue of Volume 31 (December 2008) of the Nordic Journal of Linguistics will be a special issue devoted to the syntax of nominals and noun phrases, edited by Lars-Olof Delsing and Kersti Börjars.
Deverbal nouns, lexicalization and syntactic change
Authors: Andersen Øivin
Published: May 2007

Deverbal nouns are often referred to as hybrids, containing both verbal and nominal features. In many languages deverbal nouns tend to develop into what Vendler (1967) called perfect nouns. Various stages of this development in Norwegian are proposed, drawing on Grammaticalization Theory and Lexicalization Theory. Frequency data are provided from a large newspaper corpus. The deverbal nouns are analyzed as going through a process of lexicalization where reduction in compositionality, reduced token frequency and increased idiosyncrasy are central elements. This process is triggered by relevance to the root, language use, isomorphism and the maximal difference principle. The article shows that Norwegian deverbal nouns are in a state of flux and that even different members of the same morphological type may behave quite differently syntactically and semantically.
DoesNon-Cognitivism Rest on a Mistake?
Authors: SVENSSON FRANS
Published: May 2007

Philippa Foot has recently argued that non-cognitivism rests on a mistake. According to Foot, non-cognitivism cannot properly account for the role of reasons in moral thinking. Furthermore, Foot argues that moral judgements share a conceptual structure with the kind of evaluations that we make about plants and animals, which cannot be couched in non-cognitivist terms. In this article I argue that, in the form of expressivism, non-cognitivism is capable of accommodating most of what Foot says about reasons and morality. I then argue that the kind of evaluative judgements Foot suggests that we make about plants and animals, does not constitute a plausible alternative to an expressivist understanding of moral judgements. Finally I consider an account similar to Foot's, defended by Rosalind Hursthouse, which, I argue, suffers from an inconsistency, the avoidance of which leaves Hursthouse with a view that is either compatible with expressivism or shares the same problems as Foot's.
Against Consequentialist Theories of Virtue and Vice
Authors: CALDER TODD
Published: May 2007

Consequentialist theories of virtue and vice, such as the theories of Jeremy Bentham and Julia Driver, characterize virtue and vice in terms of the consequential, or instrumental, properties of these character traits. There are two problems with theories of this sort. First they imply that, under the right circumstances, paradigmatic virtues, such as benevolence, are vices and paradigmatic vices, such as maliciousness, are virtues. This is conceptually problematic. Second, they say nothing about the intrinsic nature of the virtues and vices, which is less than we could hope for from a theory of virtue and vice. Thus, we have reason to reject consequentialist theories in favour of theories that characterize virtue and vice in terms of the intrinsic properties of these character traits. Aristotle and Thomas Hurka have theories this sort.
Inconsistency and the Theoretical Commitments of Hooker's Rule-Consequentialism
Authors: CARD ROBERT F.
Published: May 2007

Rule-consequentialism is frequently regarded as problematic since it faces the following powerful dilemma: either rule-consequentialism collapses into act-consequentialism or rule-consequentialism is inconsistent. Recent defenders of this theory such as Brad Hooker provide a careful response to this objection. By explicating the nature and theoretical commitments of rule-consequentialism, I contend that these maneuvers are not successful by offering a new way of viewing the dilemma which retains its force even in light of these recent discussions. The central idea is that even the most well-developed contemporary form of the view is ensnared in the following dilemma: as an agent-neutral consequentialist theory, rule-consequentialism is either inconsistent or it is desperately unmotivated as a form of consequentialism since it is committed to a non-consequentialist form of ultimate moral value.
THE LIMITS OF FREE SPEECH: PORNOGRAPHY AND THE QUESTION OF COVERAGE
Authors: Maitra Ishani , McGowan Mary Kate
Published: May 2007

Many liberal societies are deeply committed to freedom of speech. This commitment is so entrenched that when it seems to come into conflict with other commitments (e.g., gender equality), it is often argued that the commitment to speech must trump the other commitments. In this paper, we argue that a proper understanding of our commitment to free speech requires being clear about what should count as speech for these purposes. On the approach we defend, “speech” should get a special, technical sense, different from its ordinary sense. We offer a partial characterization of this technical sense. Finally, we argue that if certain theorists (e.g., MacKinnon) are right about what (some) pornography does, then it should fall outside the scope of the free-speech principle. If so, then contrary to first appearances, pornography may not be a case in which our commitments to freedom and gender equality come into conflict.
Childhood Onset Conduct Problems: A Preliminary Investigation into the Role of Mothers' Interpersonal Schemas and their Relationship to Parenting Behaviour
Authors: Potier Joanne , Day Crispin
Published: May 2007

Childhood onset conduct problems present some of the most significant challenges to mental health and public services today. Parent management training is among the most effective treatments for conduct problems, and yet a significant proportion of families do not benefit from this approach. This may be because key elements of parenting, such as parental cognitions, are not directly addressed in such interventions. This study investigated the role of mothers' interpersonal schemas in the maintenance of conduct problems and their relationship to parenting behaviour. It examined whether mothers of 7 to 11-year-old boys with conduct problems would have more negative child-related interpersonal schemas (Hill and Safran, 1994), and related negative parenting behaviours, observed during two parent-child interaction tasks, than mothers in a comparison group. The findings showed that there was a significant difference between the two groups in both maternal Negativity and Warmth and child-related interpersonal schemas. However, no relationship was found between parenting behaviour and child-related interpersonal schemas. The results suggest that targeting maternal cognitions in addition to negativity and warmth may enhance interventions for childhood onset conduct problems. However, more research needs to be done to ascertain which kinds of cognitions relate most closely to parenting behaviour in stressful situations.
An unusual cause of peripheral artery embolism: Floating thrombus of the thoracic aorta surgically removed
Authors: Böckler  , von Tengg-Kobligk  , Schoebinger  , Gross  , Schumacher  , Ockert  , Allenberg
Published: May 2007

Intraluminal mobile thrombus of the descending aorta are rare disorders. They are at high risk for peripheral embolism and therefore indication for treatment is mandatory. We report on a 54-year-old patient with peripheral arterial embolization who was treated by surgical thrombus removement by thoracotomy and staged peripheral bypass grafting. New diagnostic tools are presented, therapy and prognosis are discussed.
Das Klippel-Trenaunay Syndrom bei gleichzeitigem Vorliegen von Viszeralarterienaneurysmen
Authors: Pourhassan  , Grotemeyer  , Klar  , Sandmann
Published: May 2007

Das Klippel-Trenaunay Syndrom (KTS) ist eine kongenitale Angiodysplasie der venösen Gefäßstrombahn mit der Symptomtrias kutane vaskuläre Naevi, Hypertrophie einer Extremität sowie Varikose und venöse Malformation. Die Koinzidenz eines KTS mit arteriellen Malformationen im Sinne von Nierenarterienaneurysmen findet sich in der Literatur lediglich in zwei Beschreibungen. Wir berichten über einen 40-jährigen Patienten, bei dem, neben einem KTS Aneurysmen einer A. renalis, der A. lienalis, der A. mesenterica superior sowie einer A. und V. poplitea beobachtet wurden. Neben der Darstellung des diagnostischen und therapeutischen Verlaufs wird über die in der Literatur dargestellten klinischen Erfahrungen berichtet. Differentialdiagnostisch sind zwei weitere Syndrome, ebenfalls aus dem Formenkreis der Phakomatosen, abzugrenzen: das Servelle-Martorell-Syndrom und das Frederick Parkes Weber-Syndrom.
Evaluating lidar‐radar microphysics retrieval using in situ measurements
Authors: van Zadelhoff G.‐J. , Heymsfield A. J. , Donovan D. P. , McGill M. J.
Published: May 2007

This study reports on a comparison between in situ and combined lidar and radar measurements of extinction and ice water content in ice clouds. The main goal of this exercise is to verify that the lidar‐radar method can be confidently used for future satellite radar and lidar measurements. The data used in this study were obtained during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers–Florida Area Cirrus Experiment (CRYSTAL‐FACE) campaign that was conducted to study the properties of low‐latitude, continentally influenced ice cloud layers. Two different methods are used to retrieve the extinction from the lidar signal. The comparison between lidar‐derived and in situ–derived extinction values shows that they are strongly correlated for the two different lidar‐based methods. Linear fits between the ice water contents derived from the two extinctions and radar reflectivity and the in situ values result in slope parameters of 0.93 ± 0.28 and 1.09 ± 0.35. The precise values depend on the assumed ice particle properties and particle size distribution used in the lidar‐radar retrievals.
Global distributions of HO2NO2 as observed by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS)
Authors: Stiller G. P. , von Clarmann T. , Brühl C. , Fischer H. , Funke B. , Glatthor N. , Grabowski U. , Höpfner M. , Jöckel P. , Kellmann S. , Kiefer M. , Linden A. , López‐Puertas M. , Mengistu Tsidu G. , Milz M. , Steck T. , Steil B.
Published: May 2007

Stratospheric and upper tropospheric distributions of peroxynitric acid (HO2NO2) were retrieved from limb infrared spectral measurements of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on board the Environmental Satellite (ENVISAT). Single‐profile precisions are estimated at 6–14 parts per trillion by volume (pptv) in the altitude range 7–17 km and 19–34 pptv from 17 to 42 km. The vertical resolution is 5 km in the upper tropospheric and stratospheric maxima. Highest stratospheric volume mixing ratios (VMRs) reaching 310 pptv at 27 km are observed at solstice conditions in subtropical latitudes and midlatitudes at the nighttime summer hemisphere, while lowest stratospheric peak VMRs as low as 38 pptv are found during polar winter near the pole. A second maximum in the upper troposphere and lower stratosphere appears from spring to the end of summer with maximum values of 80 pptv between 7 and 14 km. Retrievals based on spectroscopic line list data instead of absorption cross sections produce HO2NO2 distributions smaller by a factor of 1.5, on average. Earlier HO2NO2 measurements from balloon instruments are in good general agreement with the presented data set if the same spectroscopic data are used. Comparisons of MIPAS HO2NO2 distributions to results of the fifth‐generation European Centre Hamburg general circulation model/Modular Earth Submodel System 1 (ECHAM5/MESSy1) provide agreement within 20% if near‐infrared photolysis is considered. With the newly available tabulated absorption cross sections and the improved photolysis modeling, former discrepancies between HO2NO2 observations and model calculations can be considered to be largely resolved.
Very high‐elevation Mont Blanc glaciated areas not affected by the 20th century climate change
Authors: Vincent C. , Le Meur E. , Six D. , Funk M. , Hoelzle M. , Preunkert S.
Published: May 2007

This paper analyses the impact of climate change over the last 100 years on high‐elevation glaciated areas of the Mont Blanc range, comprising ice fields covering the top of the Mont Blanc (4808 m) and Dôme du Goûter (4300 m) areas. Surface ablation is negligible for these high‐elevation areas and the surface mass balance is mainly controlled by snow accumulation. At Dôme du Goûter, ice fluxes have been calculated through two transversal sections by two independent methods in order to assess long‐term surface accumulation. A comparison between these results and recent accumulation observations, together with the strong relationship between valley precipitation and snow accumulation, suggests that surface accumulation rates did not change significantly over the entire 20th century. Moreover, the small ice thickness changes, less than 3 m on the average, observed at Mont Blanc and Dôme du Goûter between 1905 and 2005 clearly reveal that these high‐elevation glaciated areas have not been significantly affected by climate change over the last 100 years.
Regional variation of organic functional groups in aerosol particles on four U.S. east coast platforms during the International Consortium for Atmospheric Research on Transport and Transformation 2004 campaign
Authors: Gilardoni S. , Russell L. M. , Sorooshian A. , Flagan R. C. , Seinfeld J. H. , Bates T. S. , Quinn P. K. , Allan J. D. , Williams B. , Goldstein A. H. , Onasch T. B. , Worsnop D. R.
Published: May 2007

Submicron atmospheric aerosol samples were collected during the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) 2004 campaign on four platforms: Chebogue Point (Nova Scotia, Canada), Appledore Island (Maine), the CIRPAS Twin Otter over Ohio, and the NOAA R/V Ronald H. Brown in the Gulf of Maine. Saturated aliphatic C‐C‐H, unsaturated aliphatic C=C−H, aromatic C=C−H, organosulfur C‐O‐S, carbonyl C=O, and organic hydroxyl C‐OH functional groups were measured by calibrated Fourier Transform Infrared (FTIR) spectroscopy at all four sampling platforms. The ratio of molar concentrations of carbonyl C=O to saturated aliphatic C‐C‐H groups was nearly constant at each sampling platform, with the Twin Otter samples having the lowest ratio at 0.1 and the three more coastal platforms having ratios of 0.4 and 0.5. Organic mass (OM) to organic carbon (OC) ratios follow similar trends for the four platforms, with the Twin Otter having the lowest ratio of 1.4 and the coastal platforms having slightly higher values typically between 1.5 and 1.6. Organosulfur compounds were occasionally observed. Collocated organic aerosol sampling with two Aerodyne aerosol mass spectrometers for OM, a Sunset Laboratory thermo‐optical analysis instrument for OC, and an ion chromatography‐particle into liquid sampler (IC‐PILS) for speciated carboxylic acids provided comparable results for most of the project, tracking the time series of FTIR OM, OC, and carbonyl groups, respectively, and showing simultaneous peaks of similar magnitude during most of the project. The FTIR/IC‐PILS comparison suggests that about 9% of the carbonyl groups found in submicron organic particles on the Twin Otter are typically associated with low molecular weight carboxylic acids.
Two new non‐competitive mGlu1 receptor antagonists are potent tools to unravel functions of this mGlu receptor subtype
Authors: Knöpfel T
Published: May 2007

The validation of the selective, potent and systemically active non‐competitive mGlu1 antagonists YM‐298198 and JNJ16259685 in a physiological functional assay will facilitate elucidation of this receptor's role in brain function and as a potential drug target.

British Journal of Pharmacology (2007) 151, 723–724; doi:10.1038/sj.bjp.0707289
Propagation losses of the fundamental mode in a single line-defect photonic crystal waveguide on an InP membrane
Authors: Désières Y. , Benyattou T. , Orobtchouk R. , Morand A. , Benech P. , Grillet C. , Seassal C. , Letartre X. , Rojo-Romeo P. , Viktorovitch P.
Published: May 2007

We have investigated light propagation through a single line-defect photonic crystal waveguide on a InP membrane. Modal analysis was performed using the finite-difference time-domain method. The fundamental mode has been found to be very close to the fundamental mode in a “refractive” waveguide but, in this case, it is inherently leaky. The propagation losses of this mode in the complete three-dimensional structure have been computed and measured to determine if its use could be of interest for practical applications. Propagation losses in the range of 0.1 dB/μm have been found numerically and experimentally for the fundamental mode whereas stronger out-of-plane losses have been observed for the other leaky mode within the band gap. The origins of the out-of-plane losses were then investigated and have clarified the inherent lower leakage of the fundamental mode.
Fluid theory of magnetized plasma dynamics at low collisionality
Authors: Ramos J. J.
Published: May 2007

Finite Larmor radius (FLR) fluid equations for magnetized plasmas evolving on either sonic or diamagnetic drift time scales are derived consistent with a broad low-collisionality hypothesis. The fundamental expansion parameter is the ratio δ between the ion Larmor radius and the shortest macroscopic length scale (including fluctuation wavelengths in the absence of small scale turbulence). The low-collisionality regime of interest is specified by assuming that the other two basic small parameters—namely, the ratio between the electron and ion masses and the ratio between the ion collision and cyclotron frequencies—are comparable to or smaller than δ2. First significant order FLR equations for the stress tensors and the heat fluxes are given, including a detailed discussion of the collisional terms that need be retained under the assumed orderings and of the closure terms that need be determined kinetically. This analysis is valid for any magnetic geometry and for fully electromagnetic nonlinear dynamics with arbitrarily large fluctuation amplitudes. It is also valid for strong anisotropies and does not require the distribution functions to be close to Maxwellians. With a subsidiary small-parallel-gradient ordering for large-aspect-ratio toroidal plasmas in a strong but weakly inhomogeneous magnetic field, a new system of reduced two-fluid equations is derived, rigorously taking into account all the diamagnetic effects associated with arbitrary density and anisotropic temperature gradients.
Expansion shock waves in the implosion process from a time-reversible molecular-dynamics simulation of a dual explosion process
Authors: Komatsu Nobuyoshi , Abe Takashi
Published: May 2007

Why does not an expansion shock wave exist in a gaseous medium in nature? The reason has been widely believed to be the irreversibility in nature, while an obvious demonstration for this belief has not been accomplished yet. In order to resolve the question from a microscopic viewpoint, an implosion process dual to an explosion process was investigated by means of the molecular-dynamics method (MD). To this aim, we employed a “bit-reversible algorithm (Bit MD)” that was completely time-reversible in a microscopic viewpoint and was free from any round-off error. Here we show that, through a dual implosion simulation (i.e., a time-reversible simulation of the explosion), a kind of expansion shock wave is successfully formed in the Bit MD simulation. Furthermore, we show that when the controlled noise is intentionally added to the Bit MD, the expansion shock wave disappears dramatically and turns into an isentropic expansion wave, even if the noise is extremely small. Since the controlled noise gives rise to the irreversibility in the Bit MD simulation, it can be concluded that the irreversibility in the system prohibits the expansion shock wave from appearing in the system.
BPS domain walls and vacuum structure of N=1 supergravity coupled to a chiral multiplet
Authors: Gunara Bobby E. , Zen Freddy P. , Arianto
Published: May 2007

We study BPS domain walls of N=1 supergravity coupled to a chiral multiplet and their Lorentz invariant vacuums which can be viewed as critical points of BPS equations and the scalar potential. Supersymmetry further implies that gradient flows of BPS equations controlled by a holomorphic superpotential and the Kähler geometry are unstable near local maximum of the scalar potential, whereas they are stable around local minimum and saddles of the scalar potential. However, the analysis using renormalization group flows shows that such gradient flows do not always exist particularly in infrared region.
Reentrant cone angle dependence of the energetic electron slope temperature in high-intensity laser-plasma interactions
Authors: Nakatsutsumi M. , Kodama R. , Norreys P. A. , Awano S. , Nakamura H. , Norimatsu T. , Ooya A. , Tampo M. , Tanaka K. A. , Tanimoto T. , Tsutsumi T. , Yabuuchi T.
Published: May 2007

Energy spectra of fast electrons, generated when high-intensity laser pulses irradiated hollow conical targets, have been measured experimentally. It is shown here that the slope temperature of the fast electrons is strongly dependent on the opening angle of the cone, and has a maximum value at 25°. The data confirms optical guiding of the laser pulse, by comparison of the measured electron temperature with ray-tracing calculations that include absorption in plasmas. The enhanced energy flow and intensity induced by optical guiding of the laser pulse inside the cone as a function of the opening angle as well as the f-number of the focusing optics is discussed.
Ultrafast optical Kerr effect spectroscopy of water confined in nanopores of the gelatin gel
Authors: Ratajska-Gadomska B. , Bialkowski B. , Gadomski W. , Radzewicz Cz.
Published: May 2007

We report on the investigation of a short-time collective dynamics of water confined in the pores of the gelatin gel, using the femtosecond optical Kerr effect spectroscopy. The ultrafast responses of water molecules obtained in bulk liquid and in three concentrations of gelatin gels are explained theoretically, both in a long time and in a short time regime, taking into account all molecular motions. We prove that the contribution of molecules involved in tetrahedral, strongly H-bonded structures stabilizing the gel network increases with the gel concentration. On the other hand the long-time relaxation of water molecules is significantly slowed down in the gel pores.
Piezoelectric, dielectric, and ferroelectric properties of 0–3 ceramic/cement composites
Authors: Xin Cheng , Shifeng Huang , Jun Chang , Zongjin Li
Published: May 2007

The sulphoaluminate cement and a piezoelectric ceramic, 0.08Pb(Li1∕4Nb3∕4)O3·0.47PbTiO3·0.45PbZrO3[P(LN)ZT], were used to fabricate 0–3 cement based piezoelectric composites. The piezoelectric, dielectric, and ferroelectric properties of the composites were mainly investigated. The results indicate that the piezoelectric strain factor d33 increases as the P(LN)ZT volume fraction increases, which follows the cube model well. The dielectric constant εx and dielectric loss tan δ show similar trends with the d33. In the frequency range of 40–100 kHz, the dielectric constants of the composites decrease sharply, which is mainly attributed to interfacial polarization in the composite. Above 200 kHz, the cement-based piezoelectric composites exhibit good dielectric-frequency stability. Hysteresis measurements indicate that the composites exhibit typical ferroelectric hysteresis loops at room temperature. The remanent polarization Pr and the coercive field Ec of the composites increase as the P(LN)ZT volume fraction increases. Meanwhile, the remnant polarizations Pr shows little asymmetric characterization.
High temperature thermoelectric properties of a homologous series of n-type boron icosahedra compounds: A possible counterpart to p-type boron carbide
Authors: Mori Takao , Nishimura Toshiyuki , Yamaura Kazunari , Takayama-Muromachi Eiji
Published: May 2007

We report on the thermoelectric properties of n-type homologous boron cluster compounds REB17CN and REB22C2N (RE=rare earth) in the temperature range of 300–1000 K. Boron cluster compounds like boron carbide have predominantly exhibited p-type behavior. REB17CN and REB22C2N exhibit n-type behavior without doping and are possible counterparts to boron carbide, which is known to be an exemplar p-type high temperature thermoelectric compound. With the hot press method it was only possible to prepare samples with low density and extremely low power factors. Two methods for improving the properties were investigated: spark plasma sintering of HoB17CN and YB22C2N and seeding of ErB17CN and ErB22C2N samples with metal borides like ErB4 and ErB6. Although absolute values of the power factor are still low, both methods are shown to yield routes for large increases of the power factor (a factor of 31 to 106 times for the samples measured) compared to conventional hot pressed samples.
Studies of intersystem crossing dynamics in acetylene
Authors: Thom Ryan L. , Wong Bryan M. , Field Robert W. , Stanton John F.
Published: May 2007

We report a new ab initio study of the acetylene T3 potential energy surface, which clarifies the nature of its energy minimum, and present computed equilibrium geometries and diabatic frequencies. This information enables the computation of harmonic vibrational overlap integrals of T3 vibrational levels with the S1 3ν3 state. The results of this calculation support the interpretation of two local perturbations of S1 3ν3, revealed in ultraviolet laser-induced fluorescence/surface electron ejection by laser excited metastables spectroscopy and Zeeman anticrossing measurements, respectively, as arising from two rotational submanifolds of a single T3 vibrational state. We present plausible assignments for this state as a guide for future experimental work.
Plasma nanosheath formation with carrier accumulation and enhanced localized spontaneous emission at “quantum wedges” in textured GaN
Authors: Riyopoulos S. , Moustakas T. D. , Cabalu J. S.
Published: May 2007

It is shown that spontaneous and piezoelectric polarization fields, inherent in GaN lattices, combined with constrained carrier motion along the quantum wells, give rise to equilibrium plasma nanosheaths. Induced potentials are localized within nm Debye lengths with peak voltages much larger than the thermal carrier energy. The associated energy band-bending causes enhanced carrier accumulation at quantum wedges and quantum tips formed by intersecting quantum wells. The total carrier number over an entire quantum well (QW) also increases, compared to flat bands, manifesting spontaneous intrinsic pumping due to polarization. It follows that the spontaneous emission is localized at quantum wedges, and the total emission exceeds that from a flat quantum well of similar parameters, as experimentally observed. The sheath potentials are sufficiently high for 1D or 0D carrier localization at quantum wedges and quantum tips.
Propagation of a weakly nonlinear laser pulse in a curved plasma channel
Authors: Reitsma A. J. W. , Jaroszynski D. A.
Published: May 2007

In this paper, the propagation of a high intensity laser pulse in a curved plasma channel is studied. The matching conditions, which are different from straight plasma channels, are examined. The analysis includes a study of centroid and spot size oscillations, relativistic self-focusing, and the effect of wakefields on the propagation of the laser pulse. The possible application of curved plasma channels in laser wakefield acceleration is discussed.
On-off optical switching of the magnetic and structural properties in a spin-crossover complex
Authors: Kato K. , Takata M. , Moritomo Y. , Nakamoto A. , Kojima N.
Published: May 2007

A photoexcitation is one of the promising external fields to control the material phases. Here, the authors have demonstrated that the magnetic and structural properties of a spin-crossover complex, Fe(phen)2(NCS)2 (phen=1,10-phenanthroline), can be reversibly switched by the on-off action of the continuous photoexcitation at the same temperature. The structural data suggest that the density of the high-spin Fe2+ in the photoinduced phase is about 0.88. Suppressed atomic vibrations of the photoinduced phase exclude the conventional heating effect as the origin for the observed optical switching.
1.5
μ
m
band Hong-Ou-Mandel experiment using photon pairs generated in two independent dispersion shifted fibers
Authors: Takesue Hiroki
Published: May 2007

This letter reports a Hong-Ou-Mandel experiment using two photon pairs in the 1.5μm band that are generated in two independent dispersion shifted fibers. A quantum interference with 53% visibility was observed. Thanks to the narrow bandwidth of the photon pairs, the required accuracy for photon arrival time adjustment was relaxed to a few millimeters, which is a great advantage for an application to a quantum relay.
Ultrafast gain dynamics in 1.3μm InAs∕GaAs quantum-dot optical amplifiers: The effect of p doping
Authors: Cesari Valentina , Langbein Wolfgang , Borri Paola , Rossetti Marco , Fiore Andrea , Mikhrin S. , Krestnikov I. , Kovsh A.
Published: May 2007

Ultrafast gain dynamics of the ground-state transition are measured in electrically pumped InAs∕GaAs quantum-dot amplifiers emitting near 1.3μm at room temperature. Gain recovery on a subpicosecond time scale occurs at high electrical injection. However, when comparing p-doped and undoped devices fabricated under identical conditions and operating at the same gain, faster absorption recovery but slower gain dynamics are observed in p-doped amplifiers. The slower gain dynamics is attributed to a reduced reservoir of excited-state electrons in p-doped quantum-dot devices, which limits the recovery of the electron ground-state occupation mediated by intradot carrier-carrier scattering.
Si
∕
Si
Ge
n-type resonant tunneling diodes fabricated using in situ hydrogen cleaning
Authors: Suet Z. , Paul D. J. , Zhang J. , Turner S. G.
Published: May 2007

In situ hydrogen cleaning to reduce the surface segregation of n-type dopants in SiGe epitaxy has been used to fabricate Si∕SiGe resonant tunneling diodes in a joint gas source chemical vapor deposition and molecular beam epitaxial system. Diodes fabricated without the in situ clean demonstrate linear current-voltage characteristics, while a 15min hydrogen clean produces negative differential resistance with peak-to-valley current ratios up to 2.2 and peak current densities of 5.0A∕cm2 at 30K. Analysis of the valley current and the band structure of the devices suggest methods for increasing the operating temperature of Si∕SiGe resonant tunneling diodes as required for applications.
Epitaxial growth of sol-gel derived BiScO3–PbTiO3 thin film on Nb-doped SrTiO3 single crystal substrate
Authors: Wen Hai , Wang Xiaohui , Zhong Caifu , Shu Like , Li Longtu
Published: May 2007

Bi Sc O 3 – Pb Ti O 3 (BSPT) thin film was grown on electrical conductive Nb-doped SrTiO3 (100) (Nb-STO) single crystal substrate by a sol-gel method. The x-ray diffraction and high resolution transmission electron microscopy proved the epitaxial growth relation between the BSPT thin film and Nb-STO substrate. The [001]-epitaxial BSPT thin film exhibited considerable high remanent polarization of 74μC∕cm2 and effective piezoelectric coefficient d33* of 130pm∕V, which were much higher than those of the (100)-oriented BSPT thin film grown on traditional silicon substrate.
Highly transparent microcrystalline silicon carbide grown with hot wire chemical vapor deposition as window layers in n-i-p microcrystalline silicon solar cells
Authors: Huang Y. , Dasgupta A. , Gordijn A. , Finger F. , Carius R.
Published: May 2007

Microcrystalline silicon carbide (μc-SiC) films were prepared using hot wire chemical vapor deposition at low substrate temperature. The μc-SiC films were employed as window layers in microcrystalline silicon (μc-Si:H) n-i-p solar cells. Quantum efficiency (QE) and short circuit current density (JSC) in these n-side illuminated n-i-p cells were significantly higher than in standard p-i-n cells. A high QE current density of 26.7mA∕cm2 was achieved in an absorber layer thickness of 2μm. The enhanced JSC was attributed to the wide band gap of the μc-SiC layer and a sufficiently high hole drift mobility in μc-Si:H absorber layer.
Direct observation of electromigration-induced surface atomic steps in Cu lines by in situ transmission electron microscopy
Authors: Chen Kuan-Chia , Liao Chien-Neng , Wu Wen-Wei , Chen Lih-Juann
Published: May 2007

Surface atomic steps in unpassivated copper lines under electromigration (EM) have been directly observed in ultrahigh vacuum by in situ transmission electron microscopy (in situ TEM). The combination of {111} planes and ⟨110⟩ directions for crystalline Cu were found to be the most favored EM paths. The in situ TEM study of EM-induced evolution of Cu surface structures provides a sound basis for understanding the dependence of EM-induced atomic migration mechanism on crystal orientation of crystalline Cu. The understanding shall lead to the effective strategy of using appropriate passivation layer to suppress the electromigration.
Oribatid mites as a major dietary source for alkaloids in poison frogs
Authors: Saporito Ralph A. , Donnelly Maureen A. , Norton Roy A. , Garraffo H. Martin , Spande Thomas F. , Daly John W.
Published: May 2007

Alkaloids in the skin glands of poison frogs serve as a chemical defense against predation, and almost all of these alkaloids appear to be sequestered from dietary arthropods. Certain alkaloid-containing ants have been considered the primary dietary source, but dietary sources for the majority of alkaloids remain unknown. Herein we report the presence of ≈80 alkaloids from extracts of oribatid mites collected throughout Costa Rica and Panama, which represent 11 of the ≈24 structural classes of alkaloids known in poison frogs. Forty-one of these alkaloids also occur in the dendrobatid poison frog,
Oophaga pumilio
, which co-occurs with the collected mites. These shared alkaloids include twenty-five 5,8-disubstituted or 5,6,8-trisubstituted indolizidines; one 1,4-disubstituted quinolizidine; three pumiliotoxins; and one homopumiliotoxin. All but the last of these alkaloid classes occur widely in poison frogs. In addition, nearly 40 alkaloids of unknown structure were detected in mites; none of these alkaloids have been identified in frog extracts. Two of these alkaloids are homopumiliotoxins, five appear to be izidines, four appear to be tricyclics, and six are related in structure to poison frog alkaloids that are currently unclassified as to structure. Mites are common in the diet of
O. pumilio
, as well as in the diets of other poison frogs. The results of this study indicate that mites are a significant arthropod repository of a variety of alkaloids and represent a major dietary source of alkaloids in poison frogs.
Cost effectiveness of adult intensive care in the UK
Authors: Ridley S. , Morris S.
Published: May 2007

We wished to investigate whether intensive care represents good value for money to the National Health Service in the UK using cost‐effectiveness analysis. We developed a cost‐effectiveness model using secondary data sources to estimate the incremental cost per quality adjusted life year gained of treatment in intensive care vs non‐intensive care treatment in adults. Estimates of hospital mortality with and without intensive care were obtained from seven published studies and from data published by the Intensive Care National Audit and Research Centre. Quality of life estimates were obtained from a literature review and NHS reference costs were used. Relative to non‐intensive care treatment, the incremental cost per quality adjusted life year gained of treatment in intensive care is £7010. This figure is sensitive to the mortality risk reduction associated with intensive care. Despite the high daily cost of intensive care, its cost‐effectiveness is excellent and compares favourably with other commonly used health interventions. Our findings suggest that adult intensive care represents good value for money.
Fibreoptic intubation using three airway conduits in a manikin: the effect of operator experience*
Authors: Hodzovic I. , Petterson J. , Wilkes A. R. , Latto I. P.
Published: May 2007

In a randomised cross‐over study, 72 anaesthetists (24 Senior House Officers, 24 Specialist Registrars and 24 Consultants) attempted to place a fibreoptic scope in the trachea of a manikin using three airway conduits: the Berman airway, the LMA Classic™ and the intubating laryngeal mask airway. The time for insertion of the airway conduit, delivery of two breaths and fibreoptic scope placement in the trachea was the primary endpoint. These overall times were significantly shorter (median [interquartile range]) using the LMA Classic™ (36 [28–45]) than via the intubating laryngeal mask (54 [42–79]) and the Berman airway (45 [33–80]), p < 0.0001. Senior House Officers were significantly slower than both Specialist Registrars and Consultants (p < 0.0001). The LMA Classic™ was considered to be the easiest conduit to use for fibreoptic scope placement by all grades of anaesthetists. We conclude that the LMA Classic™ is the most effective conduit for fibreoptic scope placement especially for anaesthetists with limited experience in its use.