bluuebunny/crossref_metadata_2025 huggingface dataset:
Autonomy, Futility, and the Limits of Medicine
Authors: Schwartz Robert L.
Published: December 2009

Most of us find the surgeon's surprise at this patient' request understandable, and it is hard to imagine any surgeon acceding to this patient's demand. On the other hand (the one left), the patient is right—the surgeon is denying his technical skill because his values are different from those of the patient, whose values the surgeon does not respect. The autonomy of the patient is being limited by the values of the doctor whose own interests, other than his interest in practicing medicine according to his own ethical values, would remain unaffected by his decision to provide the service.
Mrs. Wanglie and “Doctor Knows Best” and Making Decisions for Those Who Cannot Decide for Themselves: Autonomy in Two Recent Cases
Authors: Rouse Fenella
Published: December 2009

Since at least the Karen Ann Quinlan case, the idea of autonomy has always been central to the discussion about whether to given life-prolonging treatment. Those on different sides of the debate may disagree strongly about some of the issues, but the importance of the patient's autonomy has been accepted by people of widely different points of view.
Ethics Gains a Foothold in Science and Public Policy Arenas
Authors: Phillips Donald F.
Published: December 2009

In the last issue of Cambridge Quarterly, I summarized several sessions on bioethics held at conferences sponsored by organizations that are not usually thought of as being in the mainstream of bioethics. In particular, I mentioned the American Public Health Associtation and the American Anthropological Association as examples of organizations with broad interdisciplinary memberships that have developed specialized interests in the relationships between their respective fields (Public health and anthropology) and healthcare ethics. The article pointed out that there are other voices outside the field of bioethics that make valuable contributions to the shape, function, and direction the field takes.
Partial Liver Transplantation from Living Donors
Authors: Segre Macro
Published: December 2009

The ethics committee of the University of São Paulo Medical College Hospital and Clinics has authorized partial liver transplantation from living donors. The request for this type of transplantation was brought to the committee by a team of professors of surgery operating at the university, headed by Dr. Silvano Raia. Their request and justification are presented here, with discussion following.
Ethical Issues and Transplantation Technology
Authors: Thomasma David C.
Published: December 2009

Not that long ago, any thought of transferring body parts, or fluids like blood, among individuals was expressed in terms of a nightmare. Consider the problem of involuntary blood transfusions to Count Dracula! Or recall the infamous brain transplant to the brutish body under Dr. Frankenstein's ministrations. The very thought of bodily transference stimulated writers to create monsters. The stuff of evil seemed to surround any attempt. Hubris was considered the evil that exceeded the normal limits of scientific research and development. Transplantation seemed to make humans into gods who defied death but who, like Icarus and his wax wings, flew too close to the sun.
Baby T
Authors: Goldstein David A.
Published: December 2009

The recent case of Baby Theresa has once again raised the dilemma of organ donation from anencephalic infants. Baby Theresa's distraught parents wanted to create something good from something tragic, by donating the baby's organs so that other children could live. If the physician waited for their baby to die naturally, the organs would not be suitable for transplantation. If they took them before death they could be harvested. For this reason, the parents petitioned the Florida courts to declare their baby dead at birth so the organs could be removed at an earlier, more propitious time. The court refused. The infant died, its vital organs unusable.
When Do Organs Become “Spare Parts”?
Authors: Kushner Thomasine
Published: December 2009

Baby Theresa, in her short 9-day life, cast a national spotlight on the question “Should anencephalic infants be used for organ procurement?” In denying her parents′ wishes to donate the baby's healthy organs to other children in need of kidneys, liver, heart, and lungs, Circuit Court Judge Estella Moriarty said, “I cannot authorized someone to take your baby's life, however short, however unsatisfactory, to save another child.”In citing a1988 Florida statute that does not allow a person to be declared dead while any part of the brain is functioning, Judge Moriarty ruled that doctors could only remove organs not vital to Theresa Ann's life. As the baby slowly died, so too did her vital organs.
Facilitating Healthcare Ethics Research: Assessement of Moral Reasoning and Moral Orientation from a Single Interview
Authors: Self Donnie J. , Skeel Joy D.
Published: December 2009

In recent years, the theoretical work of Gilligan in women's psychological development has led to the development of the concept of moral orientation or moral voice in contrast to the concept of moral reasoning or moral judgment developed by Kohlberg. These concepts have been of particular interest in gender studies, especially as applied to adolescence. These concepts of moral orientation and moral reasoning are being increasingly employed in healthcare ethics studies in a wide variety of settings. The recent work has included studies of physicians, nurses, dentists, veterinarians, social workers, teachers of medical ethics, and hospital ethics committees. However, the study of moral development in healthcare providers has been hampered because collecting the necessary data from healthcare workers has been labor intensive and extremely time consuming. More efficient methods are needed.
The Risks of Managing Uncertainty: The Limitations of Governance and Choice, and the Potential for Trust
Authors: Brown Patrick , Calnan Michael
Published: December 2009

The inherent problems and limitations of managing risk and uncertainty are examined in a salient case setting – the English NHS. The ‘dark-side’ of simply trusting professionals to pursue their own craft, as acknowledged by Sennett, has been politicised to under-gird an increased use of quasi-markets, via the choice agenda, and governance. It is argued that these alternatives to trust – price and control – are further dysfunctional still. The innate tendencies of governance, and therefore choice, to lose sight of patient care are even more pronounced than the fallibility of professionals. A new, qualified form of trust is proposed in resolution.
Investing in Parenting Education: A Critical Review of Policy and Provision in England
Authors: Churchill Harriet , Clarke Karen
Published: December 2009

Parenting education has been given an increasingly important role in government policies to address social exclusion. This paper examines the basis for investing in parenting programmes and reviews the various different types of parenting education provision. It discusses the evidence on the effectiveness of multi-component and group parenting programmes in modifying parent–child relationships and the outcomes for children and young people. The paper concludes that while such programmes appear to produce beneficial outcomes, it is important that they remain linked to a strategy that does not individualise the causes of social exclusion.
Disciplining ‘Problem Parents’ in the Youth Court: Between Regulation and Resistance
Authors: Holt Amanda
Published: December 2009

This paper explores the ways in which parents, who have been the recipients of Parenting Orders, perform identity work through their accounts of their experiences in court. Discourse analysis is used to identify five key ‘strategies of resistance’ through which parents manage their parental identity and argues that such discursive practices highlight the fragility of such parents' claims to a positive parental identity in light of hegemonic gendered and classed conceptions of ‘responsible parenting’. The paper concludes by reflecting on what such practices might mean for parents who find themselves at once both regulated and resistant.
The Role of Social Housing in the ‘Care’ and ‘Control’ of Tenants with Mental Health Problems
Authors: Parr Sadie
Published: December 2009

Social housing is at the intersection of two policy agendas, namely anti-social behaviour and community care. This means that tenants with mental ill-health might at once be defined as vulnerable and in need of support to enable them to live independently, but simultaneously their behaviour may be viewed as a threat to the safety of others serving to legitimatise disciplinary and punitive forms of intervention on the grounds of ‘difference’. This paper focuses on the role of housing professionals in the management of cases of ASB involving people with mental ill-health. It argues that housing practitioners are not adequately equipped to make judgements on the culpability of ‘perpetrators’ who have mental ill-health and ensure their response is appropriate. This raises questions about the training housing officers recieve, and more broadly, whether the competing policy aims of community care and ASB can be reconciled.
The Use of Anti-Social Behaviour Powers with Vulnerable Groups: Some Recent Research
Authors: Manders Gary
Published: December 2009

Research into the application of the ASB powers to various ‘vulnerable’ sections of society is under-developed. This review article discusses recent published research concerning a number of different groups, highlights key emerging themes and identifies some of the research gaps.
REDUCING COMPOSITIONAL TO DISQUOTATIONAL TRUTH
Authors: HALBACH VOLKER
Published: December 2009

Disquotational theories of truth, that is, theories of truth based on the T-sentences or similar equivalences as axioms are often thought to be deductively weak. This view is correct if the truth predicate is allowed to apply only to sentences not containing the truth predicate. By taking a slightly more liberal approach toward the paradoxes, I obtain a disquotational theory of truth that is proof theoretically as strong as compositional theories such as the Kripke–Feferman theory, although it doesn’t probe the compositional axioms.
MINIMAL TRUTH AND INTERPRETABILITY
Authors: FISCHER MARTIN
Published: December 2009

In this paper we will investigate different axiomatic theories of truth that are minimal in some sense. One criterion for minimality will be conservativity over Peano Arithmetic. We will then give a more fine-grained characterization by investigating some interpretability relations. We will show that disquotational theories of truth, as well as compositional theories of truth with restricted induction are relatively interpretable in Peano Arithmetic. Furthermore, we will give an example of a theory of truth that is a conservative extension of Peano Arithmetic but not interpretable in it. We will then use stricter versions of interpretations to compare weak theories of truth to subsystems of second-order arithmetic.
A PURELY SYNTACTIC AND CUT-FREE SEQUENT CALCULUS FOR THE MODAL LOGIC OF PROVABILITY
Authors: POGGIOLESI FRANCESCA
Published: December 2009

In this paper we present a sequent calculus for the modal propositional logic GL (the logic of provability) obtained by means of the tree-hypersequent method, a method in which the metalinguistic strength of hypersequents is improved, so that we can simulate trees shapes. We prove that this sequent calculus is sound and complete with respect to the Hilbert-style system GL, that it is contraction free and cut free and that its logical and modal rules are invertible. No explicit semantic element is used in the sequent calculus and all the results are proved in a purely syntactic way.
Règles pour les agents de la Société anglaise
Authors: Burgess C. J.
Published: December 2009

I. Les agents de la Société sont choisis, après une entrevue personnelle, par le Comité exécutif, à Londres. Les candidats, qui devront être sujets anglais, auront à remplir un formulaire d'engagement et devront être prêts à subir tout examen que le Comité jugera convenable. Il est positivement interdit aux chefs de service d'accepter comme agents de la Société aucun individu qui, pour une raison quelconque, ne se serait pas offert en personne et n'aurait pas été nommé par le Comité exécutif, à Londres.
The effect of late gestation foetal hypoglycaemia on cardiovascular and endocrine function in sheep
Authors: Cleal J. K. , Bagby S. , Hanson M. A. , Gardiner H. M. , Green L. R.
Published: December 2009

An appropriate foetal cardiovascular (CV) response to reduced substrate supply (e.g. oxygen or other nutrients) is vital for growth and development, and may impact on CV control. The prevailing nutritional environment and associated CV changes may influence subsequent CV responses to challenges during late gestation, for example, umbilical cord occlusion (UCO). We investigated the effect of low-circulating glucose on foetal CV control mechanisms and response to UCO. Under general anaesthesia, late gestation foetal sheep (n = 7, 119 days gestational age (dGA), term ∼147 days) were implanted with vascular catheters, a bladder catheter, electrocardiogram electrodes and an umbilical cord occluder. Mean arterial pressure (MAP), heart rate (HR) and kidney function were monitored during maternal saline (MSAL, 125dGA) and insulin (MINS, 126dGA) infusion, and foetal CV responses were assessed during incremental doses of angiotensin II, a 90-s total UCO, and administration of phenylephrine to assess baroreflex function. During MINS infusion, the decrease in maternal and foetal blood glucose was associated with a small but significant decrease in foetal HR and reduced foetal baroreflex sensitivity (P < 0.05). The increase in foetal MAP during a 90-s UCO was greater during hypoglycaemia (P < 0.05). The MAP response to angiotensin II was not affected by hypoglycaemia. Decreased foetal HR and baroreflex sensitivity and increased CV responsiveness to UCO during hypoglycaemia indicates altered CV homoestatic mechanisms. The combination of altered nutrition and a CV challenge, such as UCO, during late gestation may have a cumulative effect on foetal CV function.
Bifurcation and hysteresis of the magnetospheric structure with a varying southward IMF: Field topology and global three‐dimensional full particle simulations
Authors: Cai DongSheng , Tao Weifeng , Yan Xiaoyang , Lembege Bertrand , Nishikawa Ken‐Ichi
Published: December 2009

Using a three‐dimensional full electromagnetic particle model, we have performed global simulations of the interaction between the solar wind and the terrestrial magnetosphere and have investigated its asymptotic stability. The distance between the dayside magnetopause subsolar point and the Earth center, Rmp, is measured, as the intensity of southward interplanetary magnetic field (IMF) ∣Bz∣ is slowly varying. Based on the field topology theory, one analyzes the variation of Rmp as a reference index of the dynamics of this interaction, when IMF ∣Bz∣ successively increases and decreases to its original value. Two striking results are observed. First, as the IMF ∣Bz∣ increases above a critical value, the variation of Rmp suddenly changes (the so‐called bifurcation process in field topology). Above this critical value, the overall magnetic field topology changes drastically and is identified as being the signature of magnetic reconnection at the dayside magnetopause region. Second, this subsolar point recovers its original location Rmp by following different paths as the IMF ∣Bz∣ value successively increases from zero to a maximum fixed value and decreases from this maximum to zero while passing through some critical values. These different paths are the signature of a hysteresis effect and are characteristic of the so‐called subcritical‐type bifurcation. This hysteresis signature indicates that dissipation processes take place via an energy transfer from the solar wind to the magnetosphere by some irreversible way, which leads to a drastic change in the magnetospheric field topology. This hysteresis is interpreted herein as a consequence of the change of the magnetospheric field topology, or magnetic reconnection taking place at the dayside magnetopause. Sometimes, this is also called bifurcation in the nonlinear theory. The field topology reveals itself to be a very powerful tool to analyze (1) the signatures of three‐dimensional magnetic reconnection without the obligation for determining the responsible mechanisms and (2) the consequences of reconnection on the overall magnetospheric dynamics.
Multiple westward propagating signals in South Pacific sea level anomalies
Authors: Maharaj A. M. , Holbrook N. J. , Cipollini P.
Published: December 2009

The characteristics of multiple westward propagating signals in the satellite observed South Pacific sea level anomalies (SLA) between 10°S and 50°S are analyzed using the two‐dimensional Radon transform (2D‐RT). We test the hypothesis that these signals are most likely to be the signature of the first few baroclinic Rossby wave modes. This involves a comparison of the estimated phase speeds of the 2D‐RT peaks against the first four baroclinic mode Rossby wave speeds predicted from the extended theory. The 2D‐RT analysis typically identified up to three propagating signals in the SLA and very occasionally, a fourth. The first Radon transform (RT) peak phase speeds corresponded very well with first baroclinic mode Rossby wave phase speed estimates from linear theory between 15°S and 25°S and the extended theory phase speed estimates poleward of 25°S. RT peak 2 speeds were less coherent but fell within the range of extended theory estimates of the first four baroclinic Rossby wave modes, consistent with large‐scale Rossby wave dynamics. The relationship between peaks 3 and 4 and the extended theory higher‐order baroclinic mode speed estimates varied markedly across the basin. Regional variability in the spectral characteristics of the peaks suggests that different dynamical regimes dominate north and south of 30°S in the South Pacific basin. The presence of secondary peaks in the middle to high latitudes suggests that higher‐order modes may play a role in these regions.
Use of models and observations to assess trends in the 1950–2005 water balance and climate of Upper Klamath Lake, Oregon
Authors: Hostetler S. W.
Published: December 2009

A 1‐dimensional surface energy balance model is applied to produce continuous simulations of daily lake evaporation of Upper Klamath Lake, Oregon (UKL) for the period 1950–2005. The model is implemented using observed data from land‐based sites and rafts collected during 2005–2006. Progressively longer, temporally overlapping simulations are produced using observed forcing data sets from sites near UKL. Simulation of the entire 56 years is accomplished using forcing data derived from weather station data and a 1949–2007 regional climate simulation over western North America. Simulated mean annual evaporation for 1950–2005 is 1073 mm. The simulated evaporation estimates are an improvement over existing May–September pan‐derived estimates because the latter are not representative of annual evaporation rates and do not span the multidecadal period of interest over which climate‐driven interannual (and longer) variability is evident. Evaporation and the other components of the water balance display statistically significant trends over the past 56 years that are associated with changes in meteorological forcing over the lake and the radiative and moisture balances at higher elevations of the catchment. Trends in the basin are consistent with and imbedded in regional and hemispheric climate trends that have occurred over the last century.
Anelastic strain recovery reveals extension across SW Japan subduction zone
Authors: Byrne Timothy B. , Lin Weiren , Tsutsumi Akito , Yamamoto Yuhji , Lewis Jonathan C. , Kanagawa Kyuichi , Kitamura Yujin , Yamaguchi Asuka , Kimura Gaku
Published: December 2009

Sediment dominated convergent margins typically record substantial horizontal shortening often associated with great earthquakes. The convergent margin south of Japan is arguably one of the most extensively investigated margins and previous studies have documented extensive evidence for accretion and horizontal shortening. Here, we show results from anelastic strains recovered from three partially lithified sediment samples (∼40% porosities) across the southwest Japan accretionary prism and propose that the margin is dominated by horizontal extension rather than compression. The anelastic strain results are also consistent with stress directions interpreted from two independent techniques ‐ bore hole breakout orientations and core‐scale fault data. We interpret this unexpected result to reflect geologically recent underthrusting of a thick sediment package and concomitant weakening of the decollément.
Dielectric properties of lava flows west of Ascraeus Mons, Mars
Authors: Carter Lynn M. , Campbell Bruce A. , Holt John W. , Phillips Roger J. , Putzig Nathaniel E. , Mattei Stefania , Seu Roberto , Okubo Chris H. , Egan Anthony F.
Published: December 2009

The SHARAD instrument on the Mars Reconnaissance Orbiter detects subsurface interfaces beneath lava flow fields northwest of Ascraeus Mons. The interfaces occur in two locations; a northern flow that originates south of Alba Patera, and a southern flow that originates at the rift zone between Ascraeus and Pavonis Montes. The northern flow has permittivity values, estimated from the time delay of echoes from the basal interface, between 6.2 and 17.3, with an average of 12.2. The southern flow has permittivity values of 7.0 to 14.0, with an average of 9.8. The average permittivity values for the northern and southern flows imply densities of 3.7 and 3.4 g cm−3, respectively. Loss tangent values for both flows range from 0.01 to 0.03. The measured bulk permittivity and loss tangent values are consistent with those of terrestrial and lunar basalts, and represent the first measurement of these properties for dense rock on Mars.
El Niño stills winter winds across the southern Canadian Prairies
Authors: St. George Scott , Wolfe Stephen A.
Published: December 2009

Analysis of long‐term terrestrial wind speed (u) records demonstrates that interannual variability is a major component of near‐surface wind dynamics in the southern Canadian Prairies (SCP). Since the early 1950s, there have been several periods when negative anomalies in regional u persisted for 8 to 13 consecutive months, with anomalies for individual months exceeding −1 m s−1. Calm conditions on the SCP usually coincided with negative u anomalies across much of western Canada, and nearly all low‐wind events occurred during a ‘moderate’ or ‘stronger’ El Niño. Wind energy facilities in the SCP have been built during a period of relatively stable wind conditions, and the next El Niño may test their ability to maintain expected energy outputs. El Niño may affect u in other parts of the North American wind corridor and be useful for predicting seasonal or interannual changes in regional wind energy production.
Climate variability‐induced uncertainty in mid‐Holocene atmosphere‐ocean‐vegetation feedbacks
Authors: Otto J. , Raddatz T. , Claussen M.
Published: December 2009

Previous modelling studies have shown that the response of the ocean and the vegetation to mid‐Holocene insolation feeds back on the climate. There is less consensus, however, on the relative magnitude of the two feedbacks and the strength of the synergy between them. This discrepancy may arise partly from the statistical uncertainty caused by internal climate variability as the common analysis period is only about a century. Therefore, we have performed an ensemble of centennial‐scale simulations using the general circulation model ECHAM5/JSBACH‐MPIOM. The direct atmospheric response and the weak atmosphere‐vegetation feedback are statistically robust. The synergy is always weak and it changes sign between the ensemble members. The simulations, including a dynamic ocean, show a large variability at sea‐ice margins. This variability leads to a sampling error which affects the magnitude of the diagnosed feedbacks.
Molecular analysis of phosphate limitation in Geobacteraceae during the bioremediation of a uranium-contaminated aquifer
Authors: N'Guessan A Lucie , Elifantz Hila , Nevin Kelly P , Mouser Paula J , Methé Barbara , Woodard Trevor L , Manley Kimberly , Williams Kenneth H , Wilkins Michael J , Larsen Joern T , Long Philip E , Lovley Derek R
Published: December 2009

Nutrient limitation is an environmental stress that may reduce the effectiveness of bioremediation strategies, especially when the contaminants are organic compounds or when organic compounds are added to promote microbial activities such as metal reduction. Genes indicative of phosphate-limitation were identified by microarray analysis of chemostat cultures of Geobacter sulfureducens. This analysis revealed that genes in the pst-pho operon, which is associated with a high-affinity phosphate uptake system in other microorganisms, had significantly higher transcript abundance under phosphate-limiting conditions, with the genes pstB and phoU upregulated the most. Quantitative PCR analysis of pstB and phoU transcript levels in G. sulfurreducens grown in chemostats demonstrated that the expression of these genes increased when phosphate was removed from the culture medium. Transcripts of pstB and phoU within the subsurface Geobacter species predominating during an in situ uranium-bioremediation field experiment were more abundant than in chemostat cultures of G. sulfurreducens that were not limited for phosphate. Addition of phosphate to incubations of subsurface sediments did not stimulate dissimilatory metal reduction. The added phosphate was rapidly adsorbed onto the sediments. The results demonstrate that Geobacter species can effectively reduce U(VI) even when experiencing suboptimal phosphate concentrations and that increasing phosphate availability with phosphate additions is difficult to achieve because of the high reactivity of this compound. This transcript-based approach developed for diagnosing phosphate limitation should be applicable to assessing the potential need for additional phosphate in other bioremediation processes.
Eukarya 18S rRNA gene diversity in the sea surface microlayer: implications for the structure of the neustonic microbial loop
Authors: Cunliffe Michael , Murrell J Colin
Published: December 2009

We have previously shown that there is a consistent and reproducible bacterioneuston community in the surface microlayer during a fjord mesocosm experiment. One possible cause of the surface microlayer-specific bacterial community is a surface microlayer-specific protist community selectively grazing on the bacterioneuston. We determined protist community structures using Eukarya 18S rRNA gene denaturing gradient gel electrophoresis (DGGE) and subsequent DGGE band sequencing using DNA samples that were collected from the surface microlayer and subsurface water of the mesocosms. As with bacterial communities, protist community structure was consistently different in the surface microlayer when compared with subsurface water. In particular, the protist community in the surface microlayer was dominated by Cercozoa, which were not detected in the subsurface water, and Ciliophora.
Calmodulin-dependent protein kinase kinase-β activates AMPK without forming a stable complex: synergistic effects of Ca2+ and AMP
Authors: Fogarty Sarah , Hawley Simon A. , Green Kevin A. , Saner Nazan , Mustard Kirsty J. , Hardie D. Grahame
Published: December 2009

Activation of AMPK (AMP-activated protein kinase) by phosphorylation at Thr172 is catalysed by at least two distinct upstream kinases, i.e. the tumour suppressor LKB1, and CaMKKβ (Ca2+/calmodulin-dependent protein kinase kinase-β). The sequence around Thr172 is highly conserved between the two catalytic subunit isoforms of AMPK and the 12 AMPK-related kinases, and LKB1 has been shown to act upstream of all of them. In the present paper we report that none of the AMPK-related kinases tested could be phosphorylated or activated in intact cells or cell-free assays by CaMKKβ, although we did observe a slow phosphorylation and activation of BRSK1 (brain-specific kinase 1) by CaMKKα. Despite recent reports, we could not find any evidence that the α and/or β subunits of AMPK formed a stable complex with CaMKKβ. We also showed that increasing AMP concentrations in HeLa cells (which lack LKB1) had no effect on basal AMPK phosphorylation, but enhanced the ability of agents that increase intracellular Ca2+ to activate AMPK. This is consistent with the effect of AMP on phosphorylation of Thr172 being due to inhibition of dephosphorylation, and confirms that the effect of AMP is independent of the upstream kinase utilized.
HIV‐1 Tat is unconventionally secreted through the plasma membrane
Authors: Rayne Fabienne , Debaisieux Solène , Bonhoure Anne , Beaumelle Bruno
Published: December 2009

The Tat protein is required for efficient HIV‐1 (human immunodeficiency virus type 1) transcription. Moreover, Tat is secreted by infected cells, and circulating Tat can affect several cell types, thereby contributing to HIV‐1 pathogenesis. We monitored Tat secretion by transfected CD4+ T‐cells. A Tat chimaera carrying an N‐glycosylation site did not become glycosylated when expressed in cells, while the chimaera was glycosylated when mechanically introduced into purified microsomes. These data indicate that secreted Tat does not transit through the endoplasmic reticulum. The use of pharmacological inhibitors indicated that the Tat secretion pathway is unusual compared with previously identified unconventional secretion routes and does not involve intracellular organelles. Moreover, cell incubation at 16°C inhibited Tat secretion and caused its accumulation at the plasma membrane, suggesting that secretion takes place at this level.
The effect of microwave-frequency discharge-activated oxygen on the microscale structure of low-temperature water ice films
Authors: Doering Skye R. , Strobush Kirsten M. , Marschall Jochen , Boulter James E.
Published: December 2009

Low-temperature, amorphous water ice films grown by vapor deposition under high-vacuum are exposed to microwave-frequency discharge-activated oxygen in order to investigate its effect on the ice surface. Adsorption of methane is used to probe alterations to microscale structures and surface morphology. Films are interrogated throughout the experiment by grazing-angle Fourier-transform infrared reflection-absorption spectroscopy, and after the experiment by temperature-programmed desorption mass spectrometry. Multilayer Fresnel thin-film optics simulations aid in the interpretation of absorbance spectra. Using these techniques, structural alterations are observed over a range of spatial and time scales. At first, spectral absorbance features arising from incompletely coordinated water molecules disappear. The density of high-energy methane adsorption sites is reduced, lowering the equilibrium amount of adsorbed methane. At longer exposure times, this is manifested in a narrowing of the width of the primary methane desorption peak, indicating a narrower range of methane adsorption energies on the ice surface. Together these observations indicate restructuring of micropores resulting in an increase in the structural homogeneity of the film. Enhancement of small, higher-temperature methane desorption features associated with methane encapsulation during thermal annealing indicates alterations to larger pore structures by the same restructuring process. Attribution of these effects to various energetic species in active oxygen is discussed. Based on their abundance, O(P3) and O2(a Δ1g) are the most likely candidates; other trace atomic and molecular species may also contribute.
H plasma cleaning and a-Si passivation of GaAs for surface channel device applications
Authors: Marchiori C. , Webb D. J. , Rossel C. , Richter M. , Sousa M. , Gerl C. , Germann R. , Andersson C. , Fompeyrine J.
Published: December 2009

We discuss GaAs(001) cleaning and surface passivation for metal-oxide-semiconductor capacitors and field effect transistors fabricated with HfO2 as high-κ gate oxide. An amorphous-Si passivating layer is deposited by molecular beam deposition on a 2×1 reconstructed GaAs surface cleaned using a remote rf H plasma. The H plasma effectively removes C contaminants from the surface, but a progressive Ga enrichment and the presence of Ga–O bonds are observed. The capacitance-voltage measurements on capacitors under peripheral illumination show inversion, which is an indication of a passivated interface. The Dit distribution as function of energy in the band gap is extracted by using the conductance technique at high and low temperatures and is reported for HfO2/a-Si gate stacks on H-cleaned GaAs. The observed Dit distribution is asymmetric. Values as low as 7×1011 eV−1 cm−1 are found in the upper half of the band gap. One clear peak at 0.7 eV and a tail at 0.2 eV above the valence band maximum, which can be part of a second peak, are also observed. Transistor data confirm that a conducting channel is effectively opened at or very close to the GaAs surface.
Bragg reflector enhanced attenuated total reflectance
Authors: Brand S. , Abram R. A. , Kaliteevski M. A.
Published: December 2009

We model the effects of a quasibound photonic state that can exist within a substrate/metal film/Bragg reflector/air structure. The photonic state is confined as a result of total internal reflection at the air interface coupled with the effect of the photonic band gap of the Bragg reflector. The presence of the thin metallic film ensures that distinctive features are observable in the associated reflectivity spectrum. With an appropriately chosen metal layer thickness, light is able to penetrate into the structure but is then effectively trapped, leading to a greatly increased field intensity at the air interface and an associated sharp feature in the reflectivity. The sensitivity of the reflectivity feature to structural details and angle of incidence and the property of substantial field enhancement suggest that the structure could be of use in sensor/detector technology and nonlinear optics applications.
Synthesis, characterization, and magnetic properties of room-temperature nanofluid ferromagnetic graphite
Authors: Souza N. S. , Sergeenkov S. , Speglich C. , Rivera V. A. G. , Cardoso C. A. , Pardo H. , Mombrú A. W. , Rodrigues A. D. , de Lima O. F. , Araújo-Moreira F. M.
Published: December 2009

We report the chemical synthesis route, structural characterization, and physical properties of nanofluid magnetic graphite (NFMG) obtained from the previously synthesized bulk organic magnetic graphite (MG) by stabilizing the aqueous ferrofluid suspension with an addition of active cationic surfactant. The measured magnetization-field hysteresis curves along with the temperature dependence of magnetization confirmed room-temperature ferromagnetism in both MG and NFMG samples.
High resolution atomic force microscopy imaging of molecular self assembly in liquids using thermal drift corrected cantilevers
Authors: Shekhawat Gajendra S. , Chand Ami , Sharma Saurabh , Verawati  , Dravid Vinayak P.
Published: December 2009

We report on high resolution imaging of self assembled monolayers using atomic force microscopy (AFM) in aqueous environment using thermal drift corrected cantilevers. Thermal drift of the AFM probes limit the possibilities of experiments that are designed to resolve single macromolecule dynamics in aqueous conditions. We present a method of minimizing the thermal drift of the AFM cantilevers under aqueous conditions, thus paving way for getting high resolution images of molecular self assembly. This methodology, which is based on a very high resolution silicon probe attached to silicon cantilever, low-force touch due to tapping mode at each pixel in the AFM field, enables the high resolution nondestructive imaging with minimal thermal drift.
Fluorescence imaging technique of surface electrostatic potential using evanescent wave illumination
Authors: Kazoe Yutaka , Miyakawa Shu , Miki Norihisa , Sato Yohei
Published: December 2009

The electrostatic potential at a solid-liquid interface (i.e., the zeta potential) is a dominant factor in electric adsorption and microchannel flows. This study proposes a fluorescence-based technique for obtaining color image of modified surface and directly measuring zeta potential. The evanescent wave is used as an excitation light for anions and cations that emit fluorescence at two different wavelengths. Patterns of self-assembled monolayers in a closed microchannel were visualized and their zeta potential distributions were measured. This technique will contribute to development of technical applications in the fields of microfluidics and material science.
Evolution of the InAs wetting layer on GaAs(001)-c(4×4) on the atomic scale
Authors: Grabowski Jan , Prohl Christopher , Höpfner Britta , Dähne Mario , Eisele Holger
Published: December 2009

Scanning tunneling microscopy was used to investigate the development of the InAs wetting layer on the GaAs(001)-c(4×4) surface. At low InAs coverages signatures of indium agglomerations form on the surface, before an abrupt change to a (4×3) reconstructed monolayer of In2/3Ga1/3As occurs at about 2/3 ML of deposited InAs. Further indium deposition leads to a second layer with α2(2×4) and β2(2×4) structural units on the surface.
Hot electron effect in nanoscopically thin photovoltaic junctions
Authors: Kempa K. , Naughton M. J. , Ren Z. F. , Herczynski A. , Kirkpatrick T. , Rybczynski J. , Gao Y.
Published: December 2009

The open circuit voltage in ultrathin amorphous silicon solar cells is found to increase with light energy (frequency), due to extraction of hot electrons. The ultrathin nature of these junctions also leads to large internal electric fields, yielding reduced recombination and increased current. A simple phenomenological argument provides a qualitative understanding of these effects and gives guidelines for designing future, high-efficiency, hot electron solar cells.
Quantum measure and integration theory
Authors: Gudder Stan
Published: December 2009

This article begins with a review of quantum measure spaces. Quantum forms and indefinite inner-product spaces are then discussed. The main part of the paper introduces a quantum integral and derives some of its properties. The quantum integral’s form for simple functions is characterized and it is shown that the quantum integral generalizes the Lebesgue integral. A bounded, monotone convergence theorem for quantum integrals is obtained and it is shown that a Radon–Nikodym-type theorem does not hold for quantum measures. As an example, a quantum-Lebesgue integral on the real line is considered.
A limit of the confluent Heun equation and the Schrödinger equation for an inverted potential and for an electric dipole
Authors: El-Jaick Léa Jaccoud , Figueiredo Bartolomeu D. B.
Published: December 2009

We re-examine and extend a group of solutions in series of Bessel functions for a limiting case of the confluent Heun equation and, then, apply such solutions to the one-dimensional Schrödinger equation with an inverted quasiexactly solvable potential as well as to the angular equation for an electron in the field of a point electric dipole. For the first problem we find finite- and infinite-series solutions which are convergent and bounded for any value of the independent variable. For the angular equation, we also find expansions in series of Jacobi polynomials.
Procrustean rotation in concert with principal component analysis of molecular dynamics trajectories: Quantifying global and local differences between conformational samples
Authors: Oblinsky Daniel G. , VanSchouwen Bryan M. B. , Gordon Heather L. , Rothstein Stuart M.
Published: December 2009

Given the principal component analysis (PCA) of a molecular dynamics (MD) conformational trajectory for a model protein, we perform orthogonal Procrustean rotation to “best fit” the PCA squared-loading matrix to that of a target matrix computed for a related but different molecular system. The sum of squared deviations of the elements of the rotated matrix from those of the target, known as the error of fit (EOF), provides a quantitative measure of the dissimilarity between the two conformational samples. To estimate precision of the EOF, we perform bootstrap resampling of the molecular conformations within the trajectories, generating a distribution of EOF values for the system and target. The average EOF per variable is determined and visualized to ascertain where, locally, system and target sample properties differ. We illustrate this approach by analyzing MD trajectories for the wild-type and four selected mutants of the β1 domain of protein G.
Microwave measurements and ab initio calculations of structural and electronic properties of N-Et-1,2-azaborine
Authors: Tanjaroon Chakree , Daly Adam , Marwitz Adam J. V. , Liu Shih-Yuan , Kukolich Stephen
Published: December 2009

Rotational transitions for N-Et-1,2-azaborine were measured in the 5–13 GHz range using a Flygare–Balle type Fourier transform spectrometer system. Twelve distinct rotational transitions with over 130 resolved hyperfine components, which included a-dipole and b-dipole transitions, were measured and analyzed to obtain rotational constants and B11 and N14 nuclear quadrupole coupling constants in the principal rotational axis system. Rotational constants obtained are A=4477.987(4), B=1490.5083(7), and C=1230.6728(6) MHz. The quadrupole coupling constants for B11 are eQqaa=−1.82(1), (eQqbb−eQqcc)=−3.398(4) MHz, and for N14, eQqaa=1.25(1), (eQqbb−eQqcc)=0.662(4) MHz. Quantum electronic structure calculations predict a ground-state structure with the ethyl group perpendicular to the azaborine plane and rotational constants in very good agreement with the measured structure and rotational constants. The theoretical conformational analysis of the ethyl group rotation around the NC bond in relation to the heterocyclic ring yielded an asymmetric torsional potential energy surface with barrier heights of about 900 and 1350 cm−1 for the N-Et-1,2-azaborine. Results of the measurements and calculations indicate that the basic molecular structure of N-Et-1,2-azaborine is similar to ethylbenzene. Electrostatic potential calculations qualitatively show that π-electron density is somewhat delocalized around the 1,2-azaborine ring.
Intramolecular charge transfer of 4-(dimethylamino)benzonitrile probed by time-resolved fluorescence and transient absorption: No evidence for two ICT states and a πσ∗ reaction intermediate
Authors: Zachariasse Klaas A. , Druzhinin Sergey I. , Kovalenko Sergey A. , Senyushkina Tamara
Published: December 2009

For the double exponential fluorescence decays of the locally excited (LE) and intramolecular charge transfer (ICT) states of 4-(dimethylamino)benzonitrile (DMABN) in acetonitrile (MeCN) the same times τ1 and τ2 are observed. This means that the reversible LE⇄ICT reaction, starting from the initially excited LE state, can be adequately described by a two state mechanism. The most important factor responsible for the sometimes experimentally observed differences in the nanosecond decay time, with τ1(LE)<τ1(ICT), is photoproduct formation. By employing a global analysis of the LE and ICT fluorescence response functions with a time resolution of 0.5 ps/channel in 1200 channels reliable kinetic and thermodynamic data can be obtained. The arguments presented in the literature in favor of a πσ∗ state with a bent CN group as an intermediate in the ICT reaction of DMABN are discussed. From the appearance of an excited state absorption (ESA) band in the spectral region between 700 and 800 nm in MeCN for N,N-dimethylanilines with CN, Br, F, CF3, and C(O)OC2H2 p-substituents, it is concluded that this ESA band cannot be attributed to a πσ∗ state, as only the C–CN group can undergo the required 120° bending.
Low-lying absorption and emission spectra of pyrene, 1,6-dithiapyrene, and tetrathiafulvalene: A comparison between ab initio and time-dependent density functional methods
Authors: Kerkines Ioannis S. K. , Petsalakis Ioannis D. , Theodorakopoulos Giannoula , Klopper Wim
Published: December 2009

The gas-phase and in-solvent absorption and emission spectra of pyrene, 1,6-dithiapyrene, and tetrathiafulvalene are studied theoretically in the visible spectral region with the complete active space self-consistent field method, the complete active space second order perturbation theory method, and the resolution-of-identity second order perturbative corrected coupled cluster doubles (RICC2) method, with basis sets up to augmented polarized triple-ζ quality. The time-dependent density functional theory (TDDFT) formalism is also used employing a series of functionals. The nature of the excited states is discussed. With respect to literature theoretical values of the absorption and emission wavelengths of these three molecules, substantial improvements are achieved and comparison with experiment is favorable. Moreover, theoretical absorption and emission spectra of 1,6-dithiapyrene are presented for the first time. It is also exhibited that in most cases, a TDDFT treatment with hybrid functionals combined with a modest basis set (6-31G∗) appears to be capable of providing reliable estimates for absorption and emission in all three molecules with relatively low computational cost. Furthermore, the RICC2 method (standalone or in conjunction with TDDFT) provides a satisfactory ab initio alternative, providing a good compromise between accuracy and computational effort.
Hexagonal ice transforms at high pressures and compression rates directly into “doubly metastable” ice phases
Authors: Bauer Marion , Winkel Katrin , Toebbens Daniel M. , Mayer Erwin , Loerting Thomas
Published: December 2009

We report compression and decompression experiments of hexagonal ice in a piston cylinder setup in the temperature range of 170–220 K up to pressures of 1.6 GPa. The main focus is on establishing the effect that an increase in compression rate up to 4000 MPa/min has on the phase changes incurred at high pressures. While at low compression rates, a phase change to stable ice II takes place (in agreement with earlier comprehensive studies), we find that at higher compression rates, increasing fractions and even pure ice III forms from hexagonal ice. We show that the critical compression rate, above which mainly the metastable ice III polymorph is produced, decreases by a factor of 30 when decreasing the temperature from 220 to 170 K. At the highest rate capable with our equipment, we even find formation of an ice V fraction in the mixture, which is metastable with respect to ice II and also metastable with respect to ice III. This indicates that at increasing compression rates, progressively more metastable phases of ice grow from hexagonal ice. Since ices II, III, and V differ very much in, e.g., strength and rheological properties, we have prepared solids of very different mechanical properties just by variation in compression rate. In addition, these metastable phases have stability regions in the phase diagrams only at much higher pressures and temperatures. Therefore, we anticipate that the method of isothermal compression at low temperatures and high compression rates is a tool for the academic and industrial polymorph search with great potential.
Radiative heat transfer at nanoscale mediated by surface plasmons for highly doped silicon
Authors: Rousseau Emmanuel , Laroche Marine , Greffet Jean-Jacques
Published: December 2009

In this letter, we revisit the role of surface plasmons for nanoscale radiative heat transfer between doped silicon surfaces. We derive a new accurate and closed-form expression of the radiative near-field heat transfer. We also analyze the flux and find that there is a doping level that maximizes the heat flux.