bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct measurement of thermal conductivity of aluminum nanowires
Authors: Stojanovic N. , Berg J. M. , Maithripala D. H. S. , Holtz M.
Published: September 2009

A nanofabricated electrothermal test structure is reported for directly measuring the thermal conductivity of aluminum nanowires near room temperature. Interdigitated nanowires perturb an otherwise symmetric heater-sensor structure analogous to an electrical bridge circuit. Nanowires studied are 100 nm thick with 75, 100, and 150 nm widths. Finite element simulation accounts for complex device geometry. Thermal conductivity and electrical resistivity vary significantly with nanowire dimensions. Electron transport equation models which adequately describe the resistivity data consistently underestimate the thermal conductivity. Incorporating a phonon contribution of ∼21 W/m K to the total thermal conductivity is found to accurately describe the measured values.
Micro-pixel array of organic light-emitting diodes applying imprinting technique with a polymer replica
Authors: Park Tae Hyun , Kim Young Min , Park Young Wook , Choi Jin Hwan , Jeong Jin-Wook , Dong Ki Young , Choi Kyung Cheol , Ju Byeong-Kwon
Published: September 2009

Efficient micro-pixel array of small molecule organic light-emitting diodes (OLEDs) has been fabricated by an imprinting technique which uses a polymer replica. To confirm the effect of the oxygen plasma for removing the residual layer, the performance of two kinds of OLEDs with varying thicknesses of resin as the micro-pixel array, have been compared. The measured results of the OLEDs have shown comparable device performances that are significantly characterized depending on the residues on the substrate. The performance of enhanced device has achieved efficiencies of 3.6 cd/A and 1.9 lm/W at 20 mA/cm2.
Three-dimensional spin structure in exchange-biased antiferromagnetic/ferromagnetic thin films
Authors: Morales R. , Vélez M. , Petracic O. , Roshchin Igor V. , Li Z.-P. , Batlle X. , Alameda J. M. , Schuller Ivan K.
Published: September 2009

A coexistence of lateral and in-depth domain walls in antiferromagnet/ferromagnet (AF/FM) thin films exhibiting double hysteresis loops (DHLs) is demonstrated. Comparison of single and DHLs together with local and global measurements confirms the formation of two oppositely oriented domains in the AF that imprint a lateral domain structure into the FM layer. Most significantly, the magnetization reversal mechanism within each opposite domain takes place by incoherent rotation of spring-like domain walls extending through the Ni thickness. Therefore, complex three-dimensional domain walls are created perpendicular and parallel to the AF/FM interface in exchange biased systems.
Formation of globules and aggregates of DNA chains in DNA/polyethylene glycol/monovalent salt aqueous solutions
Authors: Kawakita H. , Uneyama T. , Kojima M. , Morishima K. , Masubuchi Y. , Watanabe H.
Published: September 2009

It has been known that giant DNA shows structural transitions in aqueous solutions under the existence of counterions and other polymers. However, the mechanism of these transitions has not been fully understood. In this study, we directly observed structures of probed (dye-labeled), dilute DNA chains in unprobed DNA/polyethylene glycol (PEG)/monovalent salt (NaCl) aqueous solutions with fluorescent microscopy to examine this mechanism. Specifically, we varied the PEG molecular weight and salt concentration to investigate the effect of competition between the depletion and electrostatic interactions on the coil-globule transition and the aggregate formation. It was found that the globules coexist with the aggregates when the unprobed DNA chains have a concentration higher than their overlap concentration. We discuss the stability of the observed structures on the basis of a free energy model incorporating the attractive depletion energy, the repulsive electrostatic energy, and the chain bending energy. This model suggested that both of the globules and aggregates are more stable than the random coil at high salt concentrations/under existence of PEG and the transition occurs when the depletion interaction overwhelms the electrostatic interaction. However, the coexistence of the globule and aggregate was not deduced from the thermodynamic model, suggesting a nonequilibrium aspect of the DNA solution and metastabilities of these structures. Thus, the population ratio of globules and aggregates was also analyzed on the basis of a kinetic model. The analysis suggested that the depletion interaction dominates this ratio, rationalizing the coexistence of globules and aggregates.
Ion distribution around a charged rod in one and two component solvents: Preferential solvation and first order ionization phase transition
Authors: Okamoto Ryuichi , Onuki Akira
Published: September 2009

In one and two component polar solvents, we calculate the counterion distribution around an ionizable rod treating the degree of ionization α as an annealed variable dependent on its local environment. In the two component case, we take into account the preferential solvation of the charged particles and the short-range interaction between the rod and the solvent. It follows a composition-dependent mass action law. The composition becomes heterogeneous around a charged rod on a mesoscopic scale, strongly affecting the counterion distribution. We predict a first order phase transition of weak-to-strong ionization for hydrophobic chains. This transition line starts from a point on the solvent coexistence curve and ends at an ionization critical point. The composition heterogeneity is long-ranged near the solvent critical point.
Similarity theory of nonlinear cold pair-plasma dynamics
Authors: Diver D. A. , Laing E. W.
Published: September 2009

In this article the waves and dynamics of an inhomogeneous cold magnetized electron-positron plasma are investigated using similarity methods to study particular classes of plasma wave behavior. A cold two-fluid plasma model in a cylindrical geometry (ρ,θ,z) and time t is assumed, but attention is restricted to (ρ,t) variations only. The application of similarity procedures reduces the set of partial differential equations which describe the spatial and temporal evolution of the plasma to a set of ordinary differential equations. This model has particular relevance to the description of the evolution of the electron-positron component of pulsar magnetospheres. Some typical solutions of these similarity equations are presented which characteristically have the property of blow-up phenomena.
On-chip terahertz Goubau-line waveguides with integrated photoconductive emitters and mode-discriminating detectors
Authors: Dazhang L. , Cunningham J. , Byrne M. B. , Khanna S. , Wood C. D. , Burnett A. D. , Ershad S. M. , Linfield E. H. , Davies A. G.
Published: September 2009

We have measured the picosecond time-domain response of Goubau-line waveguides, formed on quartz substrates, by integrating regions of low-temperature-grown gallium arsenide into the waveguides to act both as pulsed current emitters and detectors. Using one pair of photoconductive switches for excitation and a second pair for detection, pulsed signal propagation of a low dispersion electric field mode was demonstrated in the Goubau-lines, with the signal bandwidth extending beyond 800 GHz. Furthermore, it was demonstrated that terahertz bandstop filters can be integrated into a Goubau-line for removal of specific frequencies from the transmitted pulses.
Gate-controlled current switch in graphene
Authors: Sääskilahti Kimmo , Harju Ari , Pasanen Pirjo
Published: September 2009

We numerically study cross conductances in a four-terminal all-graphene setup. We show that far away from the Dirac point, current flows along zigzag directions, giving the possibility to guide the current between terminals using a tunable pn-junction. The device operates as a gate-controlled current switch, and the electronic properties of graphene are crucial for efficient performance.
Depth-profiling of elastic inhomogeneities in transparent nanoporous low-k materials by picosecond ultrasonic interferometry
Authors: Mechri C. , Ruello P. , Breteau J. M. , Baklanov M. R. , Verdonck P. , Gusev V.
Published: September 2009

We achieve depth-profiling of the elasticity of a thin transparent film of a nanoporous low-k material using picosecond acoustic interferometry. The variation in the material properties with depth is extracted from time-resolved femtosecond optical reflectivity measurements. More than 40% of the variation in the longitudinal elastic modulus between the front and the back surfaces of an 800 nm thick nanoporous layer is mapped with a 40 nm spatial resolution. We attribute this variation to the spatially inhomogeneous UV curing of the film during fabrication.
Excited state surfaces in density functional theory: A new twist on an old problem
Authors: Wiggins Paul , Williams J. A. Gareth , Tozer David J.
Published: September 2009

Excited state surfaces in density functional theory and the problem of charge transfer are considered from an orbital overlap perspective. For common density functional approximations, the accuracy of the surface will not be uniform if the spatial overlap between the occupied and virtual orbitals involved in the excitation has a strong conformational dependence; the excited state surface will collapse toward the ground state in regions where the overlap is very low. This characteristic is used to predict and to provide insight into the breakdown of excited state surfaces in the classic push-pull 4-(dimethylamino)benzonitrile molecule, as a function of twist angle. The breakdown is eliminated using a Coulomb-attenuated functional. Analogous situations will arise in many molecules.
Gain-length scaling in quantum dot/quantum well infrared photodetectors
Authors: Yamanaka T. , Movaghar B. , Tsao S. , Kuboya S. , Myzaferi A. , Razeghi M.
Published: September 2009

The gain in quantum dot/quantum well infrared photodetectors is investigated. The scaling of the gain with device length has been analyzed, and the behavior agrees with the previously proposed model. We conclude that we understand the gain in the low bias region, but in the high field region, discrepancies remain. An extension of the gain model is presented to cover the very high electric field region. The high field data are compared to the extended model and discussed.
Room temperature negative differential resistance of a monolayer molecular rotor device
Authors: Xue Mei , Kabehie Sanaz , Stieg Adam Z. , Tkatchouk Ekaterina , Benitez Diego , Stephenson Rachel M. , Goddard William A. , Zink Jeffrey I. , Wang Kang L.
Published: September 2009

An electrically driven molecular rotor device comprised of a monolayer of redox-active ligated copper compounds sandwiched between a gold electrode and a highly doped P+Si substrate was fabricated. Current-voltage spectroscopy revealed a temperature-dependent negative differential resistance (NDR) associated with the device. Time-dependent density functional theory suggests the source of the observed NDR to be redox-induced ligand rotation around the copper metal center, an explanation consistent with the proposed energy diagram of the device. An observed temperature dependence of the NDR behavior further supports this hypothesis.
Optical injection and detection of ballistic pure spin currents in Ge
Authors: Loren Eric J. , Ruzicka Brian A. , Werake Lalani K. , Zhao Hui , van Driel Henry M. , Smirl Arthur L.
Published: September 2009

Ballistic pure spin currents are injected into Ge at 295 K using quantum interference between one and two photon absorption processes for 1786 and 893 nm, 200 fs optical pulses. The spin currents are spatially and temporally detected using polarization- and phase-dependent differential transmission techniques with nanometer spatial and femtosecond temporal resolution. We interpret the dynamics in terms of the fast spin relaxation of the holes and intervalley transfer of electrons.
Effect of microcontent of oil in water under confined condition
Authors: Ma Liran , Luo Jianbin , Zhang Chenhui , Liu Shuhai , Zhu Tao
Published: September 2009

The lubricant film thickness between two contacting surfaces is important for the evaluation of lubrication effectiveness. According to the elastohydrodynamic lubrication theory, the film thickness of pure water is usually on the order of a few nanometers. It was found, however, that microcontent of oil contamination can cause a lubricant film more than 100 nm, much thicker than the predicted. The effect of micro-oil content in water between a smooth plate and a highly polished steel ball was investigated. The film forming characteristic of such films was presented. The film formation mechanism and influencing factors were discussed.
The p53 target Wig-1 regulates p53 mRNA stability through an AU-rich element
Authors: Vilborg Anna , Glahder Jacob A. , Wilhelm Margareta T. , Bersani Cinzia , Corcoran Martin , Mahmoudi Salah , Rosenstierne Maiken , Grandér Dan , Farnebo Marianne , Norrild Bodil , Wiman Klas G.
Published: September 2009

The p53 target gene
Wig-1
encodes a double-stranded-RNA-binding zinc finger protein. We show here that Wig-1 binds to p53 mRNA and stabilizes it through an AU-rich element (ARE) in the 3′ UTR of the p53 mRNA. This effect is mirrored by enhanced p53 protein levels in both unstressed cells and cells exposed to p53-activating stress agents. Thus, the p53 target Wig-1 is a previously undescribed ARE-regulating protein that acts as a positive feedback regulator of p53, with implications both for the steady-state levels of p53 and for the p53 stress response. Our data reveal a previously undescribed link between the tumor suppressor p53 and posttranscriptional gene regulation via AREs in mRNA.
Coexistence of binocular integration and suppression determined by surface border information
Authors: Su Yong , He Zijiang J. , Ooi Teng Leng
Published: September 2009

The visual system relies on both the integration and interocular inhibitory processes to achieve single vision from different images in the two eyes. It is generally assumed that the integration process first searches for matching local features between the two eyes. If the matching fails, an interocular inhibitory process is triggered to suppress the image representation of one eye, leading to visual perception that is essentially contributed by the other eye. Here, using a stimulus comprising of binocularly corresponding features (vertical gratings) but incompatible surface border information, we found evidence to the contrary. In one half-image, a circular patch of vertical grating was phase-shifted relative to the surrounding vertical grating to create a circular, monocular boundary contour (MBC), while the other half-image had a similar vertical grating. The two half-images had a binocular disparity at the circular grating patch area, leading to the percept of a disc in depth. Concurrent with the stereo percept, threshold for detecting a Gabor probe on the half-image without the MBC was higher than that on the corresponding area with the grating disc, indicating binocular suppression. These findings reveal that when we perceive depth, which requires the integration process to obtain binocular disparity from the two eyes, one eye's image could simultaneously be suppressed from visual awareness by the interocular inhibitory process. Our study also presents a provocative example of where the brain selectively binds some, but not all, features of the images from the two eyes for visual perception.
Phosphorylation of WASp is a key regulator of activity and stability in vivo
Authors: Blundell Michael P. , Bouma Gerben , Metelo Joao , Worth Austen , Calle Yolanda , Cowell Lucy A. , Westerberg Lisa S. , Moulding Dale A. , Mirando Samuel , Kinnon Christine , Cory Giles O. , Jones Gareth E. , Snapper Scott B. , Burns Siobhan O. , Thrasher Adrian J.
Published: September 2009

The Wiskott-Aldrich syndrome protein (WASp) is a key cytoskeletal regulator in hematopoietic cells. Covalent modification of a conserved tyrosine by phosphorylation has emerged as an important potential determinant of activity, although the physiological significance remains uncertain. In a murine knockin model, mutation resulting in inability to phosphorylate Y293 (Y293F) mimicked many features of complete WASp-deficiency. Although a phosphomimicking mutant Y293E conferred enhanced actin-polymerization, the cellular phenotype was similar due to functional dysregulation. Furthermore, steady-state levels of Y293E-WASp were markedly reduced compared to wild-type WASp and Y293F-WASp, although partially recoverable by treatment of cells with proteasome inhibitors. Consequently, tyrosine phosphorylation plays a critical role in normal activation of WASp in vivo, and is indispensible for multiple tasks including proliferation, phagocytosis, chemotaxis, and assembly of adhesion structures. Furthermore, it may target WASp for proteasome-mediated degradation, thereby providing a default mechanism for self-limiting stimulation of the Arp2/3 complex.
Protein contents in biological membranes can explain abnormal solvation of charged and polar residues
Authors: Johansson Anna C. V. , Lindahl Erik
Published: September 2009

Transmembrane helices are generally believed to insert into membranes based on their hydrophobicity. Nevertheless, there are important exceptions where polar residues have great functional importance, for instance the S4 helix of voltage-gated ion channels. It has been shown experimentally that insertion can be accomplished by hydrophobic counterbalance, predicting an arginine insertion cost of only 2.5 kcal/mol, compared with 14.9 kcal/mol in cyclohexane. Previous simulations of pure bilayers have produced values close to the pure hydrocarbon, which has lead to spirited discussion about the experimental conditions. Here, we have performed computer simulations of models better mimicking biological membranes by explicitly including protein helices at mass fractions from 15% to 55%, as well as an actual translocon. This has a striking effect on the solvation free energy of arginine. With some polar residues present, the solvation cost comes close to experimental observation at approximately 30% mass fraction, and negligible at 40%. In the presence of a translocon in the membrane, the cost of inserting arginine next to the lateral gate can be as low as 3–5 kcal/mol. The effect is mainly due to the extra helices making it easier to retain hydration water. These results offer a possible explanation for the discrepancy between the in vivo hydrophobicity scale and computer simulations and highlight the importance of the high protein contents in membranes. Although many membrane proteins are stable in pure bilayers, such simplified models might not be sufficiently accurate for insertion of polar or charged residues in biological membranes.
Hydrogen is a preferred intermediate in the energy-conserving electron transport chain of
Methanosarcina barkeri
Authors: Kulkarni Gargi , Kridelbaugh Donna M. , Guss Adam M. , Metcalf William W.
Published: September 2009

Methanogens use an unusual energy-conserving electron transport chain that involves reduction of a limited number of electron acceptors to methane gas. Previous biochemical studies suggested that the proton-pumping F
420
H
2
dehydrogenase (Fpo) plays a crucial role in this process during growth on methanol. However,
Methanosarcina barkeri
Δ
fpo
mutants constructed in this study display no measurable phenotype on this substrate, indicating that Fpo plays a minor role, if any. In contrast, Δ
frh
mutants lacking the cytoplasmic F
420
-reducing hydrogenase (Frh) are severely affected in their ability to grow and make methane from methanol, and double Δ
fpo
/Δ
frh
mutants are completely unable to use this substrate. These data suggest that the preferred electron transport chain involves production of hydrogen gas in the cytoplasm, which then diffuses out of the cell, where it is reoxidized with transfer of electrons into the energy-conserving electron transport chain. This hydrogen-cycling metabolism leads directly to production of a proton motive force that can be used by the cell for ATP synthesis. Nevertheless,
M. barkeri
does have the flexibility to use the Fpo-dependent electron transport chain when needed, as shown by the poor growth of the Δ
frh
mutant. Our data suggest that the rapid enzymatic turnover of hydrogenases may allow a competitive advantage via faster growth rates in this freshwater organism. The mutant analysis also confirms the proposed role of Frh in growth on hydrogen/carbon dioxide and suggests that either Frh or Fpo is needed for aceticlastic growth of
M. barkeri
.
Validation-based insertional mutagenesis identifies lysine demethylase FBXL11 as a negative regulator of NFκB
Authors: Lu Tao , Jackson Mark W. , Singhi Aatur D. , Kandel Eugene S. , Yang Maojing , Zhang Yi , Gudkov Andrei V. , Stark George R.
Published: September 2009

We describe a highly efficient use of lentiviral validation-based insertional mutagenesis (VBIM) to generate large populations of mammalian cells in which a strong promoter is inserted into many different genomic loci, causing greatly increased expression of downstream sequences. Many different selections or screens can follow, to isolate dominant mutant clones with a desired phenotypic change. The inserted promoter can be excised or silenced at will, to prove that the insertion caused the mutation. Cloning DNA flanking the insertion site identifies the locus precisely. VBIM virus particles are pseudotyped with VSV G protein, allowing efficient infection of most mammalian cell types, including non-dividing cells, and features are included that give high yields of stable virus stocks. In several different selections, useful mutants have been obtained at frequencies of approximately 10
−6
or higher. We used the VBIM technique to isolate mutant human cells in which the F-box leucine-rich protein 11 (FBXL11), a histone H3K36 demethylase, is shown to be a negative regulator of NFκB. High levels of FBXL11 block the ability of NFκB to bind to DNA or activate gene expression, and siRNA-mediated reduction of FBXL11 expression has the opposite effects. The H212A mutation of FBXL11 abolishes both its histone H3K36 demethylase activity and its ability to inhibit NFκB. Thus, we have used a powerful tool for mutagenesis of mammalian cells to reveal an aspect of the complex regulation of NFκB-dependent signaling.
The influence of cognitive ability and instructional set on causal conditional inference
Authors: Evans Jonathan St. B. T. , Handley Simon J. , Neilens Helen , Over David
Published: September 2009

We report a large study in which participants are invited to draw inferences from causal conditional sentences with varying degrees of believability. General intelligence was measured, and participants were split into groups of high and low ability. Under strict deductive-reasoning instructions, it was observed that higher ability participants were significantly less influenced by prior belief than were those of lower ability. This effect disappeared, however, when pragmatic reasoning instructions were employed in a separate group. These findings are in accord with dual-process theories of reasoning. We also took detailed measures of beliefs in the conditional sentences used for the reasoning tasks. Statistical modelling showed that it is not belief in the conditional statement per se that is the causal factor, but rather correlates of it. Two different models of belief-based reasoning were found to fit the data according to the kind of instructions and the type of inference under consideration.
The specific-word frequency effect in speech production: Evidence from Spanish and French
Authors: Cuetos Fernando , Bonin Patrick , Alameda José Ramón , Caramazza Alfonso
Published: September 2009

The role of word frequency in lexical access during the production of homophones remains unresolved. In the current study, we address whether specific-word (the frequency of occurrence of the word “ nun”) or homophone frequency (the summed frequency of words with the pronunciation /nλn/) determines the production latencies of homophones. In Experiments 1a, 2a, and 3a, participants named pictures of high-frequency (e.g., “ banco”–a bank: financial institution) and low-frequency (e.g., “ banco”–park bench) Spanish (Experiments 1a and 2a) or French (Experiment 3a) homophones and control pictures of nonhomophone words matched in frequency with each of the two uses of the homophones. The naming latencies for low-frequency homophones were longer than those for high-frequency homophones. Furthermore, the naming latencies for homophones were indistinguishable from those for nonhomophone controls matched in specific-word frequency. In Experiments 1b, 2b, and 3b, the participants performed either object decision or picture–word matching tasks with the stimuli used in the corresponding Experiments 1a, 2a, and 3a. There were no reliable differences between high- and low-frequency homophones. The findings support the hypothesis that specific-word and not homophone frequency determines lexical access in speech production.
Attentional control settings prevent abrupt onsets from capturing visual spatial attention
Authors: Al-Aidroos Naseem , Harrison Stephenie , Pratt Jay
Published: September 2009

When a visual distractor appears earlier than a visual target in a target-detection task, response time is faster if the distractor appears at the same location as the target. When a visual distractor appears concurrently with a visual target in a target-detection task, response time is slowed relative to when no distractor is presented. Both effects have been taken as evidence of the capture of visual spatial attention, yet capture by early distractors is contingent on top-down attentional control settings (ACSs), and capture by concurrent distractors is not. The present study evaluated whether this incongruity is attributable to the timing of distractors (earlier than vs. concurrently with the target), or to the employed comparisons (same location/different location vs. distractor/no distractor). Using a task that presented both early and concurrent distractors, we observed that, regardless of timing, capture was contingent on ACSs when assessed by the same-location/different-location comparison. This result suggests that, although irrelevant stimuli cause nonspatial purely stimulus-driven effects, the capture of visual spatial attention is contingent on ACSs.
Habitat availability, hunting or poaching: what affects distribution and density of large mammals in western Tanzanian woodlands?
Authors: Waltert Matthias , Meyer Britta , Kiffner Christian
Published: September 2009

Game reserves (GR) in Tanzania have been found to support similar or lower densities of large mammals compared with National parks (NP). But as these areas usually differ considerably not only in regard to management but also to environmental factors, we assessed the relative importance of vegetation cover, species‐specific habitat preferences and legal (trophy hunting) and illegal off‐take for observed differences in species‐specific densities. In the Katavi ecosystem, open habitats were characteristic elements of Katavi NP, while Rukwa GR was dominated by miombo forest. In an inter‐specific comparison, density differences were moderately correlated with preferences for open habitats, and with estimates of combined legal and illegal off‐take but not with one of these separately. In a multiple linear regression, open habitat preference was found to explain 39.6% of the density differences between the two protected areas. This analysis suggests that the broad‐scale pattern of most species’ distributions is governed by differing vegetation cover but that several species are overexploited by illegal (elephant, giraffe, buffalo, bush pig, warthog) or combined off‐take (hippopotamus, eland, waterbuck), thus emphasizing the need for quota readjustments and a more efficient anti‐poaching control.
Wild coffee management and plant diversity in the montane rainforest of southwestern Ethiopia
Authors: Schmitt Christine B. , Senbeta Feyera , Denich Manfred , Preisinger Helmut , Boehmer Hans Juergen
Published: September 2009

Coffea arabica occurs naturally in the montane rainforests of Ethiopia, but large areas of these unique forests have been converted to other land‐uses. In the remaining forest, wild coffee is managed and harvested with increasing intensity because of rising coffee prices in the world market. This study evaluated the impact of coffee management on wild coffee populations and the forest vegetation as a basis for conservation planning in southwestern Ethiopia. Vegetation surveys and yield assessments were carried out in unmanaged natural forest and in managed semi‐forest coffee (SFC) systems. Analyses show that wild coffee density and coffee yields were low in natural forest (max. 15 kg ha−1 year−1). In SFC systems, 30% of the canopy trees and most undergrowth vegetation were removed. This stimulated wild coffee growth and strongly enhanced yields (max. 54 kg ha−1 year−1), but severely disturbed forest structure. Species richness increased by 26% because of an increase in species of ruderal and secondary vegetation; however, species richness and abundance of typical forest species declined. Conservation of the natural forest therefore requires the control of wild coffee management. Wild coffee certification is discussed as one tool to reconcile conservation measures and the interests of local farmers.
Lobar torsion following thoraco‐abdominal oesophagogastrectomy
Authors: Felmine V. , Zuleika M.
Published: September 2009

Following thoraco‐abdominal oesophagogastrectomy for an adenocarcinoma of the lower oesophagus, an 81‐year‐old female with no pre‐existing respiratory disease could not be weaned from mechanical ventilation. Right upper and middle lobe torsion were found at thoracotomy on the 14th postoperative day. Both lobes were resected. The patient was discharged from hospital after several postoperative complications. Pulmonary torsion is a rare, potentially life‐threatening complication of thoraco‐abdominal oesophagogastrectomy. Differentiation from the more common postoesophagectomy pulmonary complications can be difficult. Early post‐thoracotomy lung opacification, in the absence of the expected degree of hypoxaemia, should trigger a suspicion of pulmonary torsion.
A meta‐analysis of the prospective randomised trials of coronary revascularisation before noncardiac vascular surgery with attention to the type of coronary revascularisation performed
Authors: Biccard B. M. , Rodseth R. N.
Published: September 2009

Prospective randomised trials of coronary revascularisation prior to noncardiac surgery have shown no survival benefit following noncardiac surgery. However, these studies have not differentiated the outcomes associated with coronary artery bypass grafting (CABG) and percutaneous coronary interventions. We performed a meta‐analysis of the randomised controlled trials of pre‐operative coronary revascularisation for noncardiac surgery, extracting data for 30 day and long term all‐cause mortality and myocardial infarction (MI) following revascularisation, according to the type of revascularisation performed. Pre‐operative percutaneous coronary intervention was associated with significantly increased 30 day MI and composite death and MI. Pre‐operative CABG was associated with a significantly improved long term composite outcome of death and MI compared to percutaneous coronary interventions. The adverse effect of percutaneous coronary interventions on both short and long term outcomes in vascular surgical patients should be taken into consideration when interpreting these trials. CABG may improve long term outcomes in vascular surgical patients. The indications for and timing of CABG in vascular surgical patients needs further research.
Fibreoptic intubation through the laryngeal mask airway: effect of operator experience*
Authors: Hodzovic I. , Janakiraman C. , Sudhir G. , Goodwin N. , Wilkes A. R. , Latto I. P.
Published: September 2009

In a randomised crossover study, we compared times and success rates for tracheal placement of a fibrescope and railroading of a tracheal tube through the classic laryngeal mask airway by anaesthetists with limited experience in fibreoptic intubation (trainees) and those who were experts. Thirty‐two patients, 32 trainees and three experts took part. The median (IQR [range]) times to fibrescope placement for trainees and experts were 21 (18–30 [12–58]) s and 17 (14–24 [9–55]) s, respectively (95% CI for the difference 2–8 s; p = 0.023). There were no significant differences between trainees and experts in the times to placement of the laryngeal mask airway (41 (33–47 [31–105]) s and 36 (33–43 [30–52]) s, respectively; p = 0.24), railroading times (43 (40–58 [33–87]) s and 44 (38–57 [31–83]) s, respectively; p = 0.96) and total intubation time (114 (97–127 [80–213]) s and 95 (89–116 [74–139]) s, respectively; p = 0.13). There was no significant difference in the number of attempts needed for successful placement of the fibrescope (p = 0.12) and railroading the tracheal tube (p = 0.22). The differences between experts and trainees when using fibrescope assisted intubation via the classic laryngeal mask airway were not clinically important.
Pre‐operative forced‐air warming as a method of anxiolysis
Authors: Wen R. J. , Leslie K. , Rajendra P.
Published: September 2009

We tested the hypothesis that pre‐operative forced‐air warming is as effective for anxiolysis as intravenous midazolam, using a blinded, placebo controlled factorial design. One hundred and twenty patients were randomly assigned to cotton blanket and saline injection (n = 30), forced‐air warmer and saline injection (n = 30), midazolam 30 μg.kg−1 and cotton blanket (n = 30), and forced‐air warmer and midazolam 30 μg.kg−1 (n = 30). Patients completed visual analogue scales for anxiety and thermal comfort, and the State‐Trait Anxiety Inventory, at baseline and after 20 min. The estimated effect of midazolam on visual analogue scores for anxiety was −10 (95% CI −3 to −18; p = 0.007) and on state anxiety was −5 (95% CI −7 to −4; p = 0.03). Warming had no influence on visual analogue scores for anxiety (p = 0.50) or state anxiety (p = 0.33), but its estimated effect on thermal comfort was +23 (95% CI 19–27; p < 0.0001). There was no interaction between midazolam and warming. Pre‐operative warming was not equivalent to midazolam for anxiolysis and cannot be recommended solely for this purpose.
Retrograde tracheal intubation
Authors: Dhara S. S.
Published: September 2009

Successful management of difficult tracheal intubation by retrograde intubation has been reported for almost 50 years and can be used whether or not it is anticipated. There are numerous reports of variations to the basic technique to enhance reproducibility of this guided blind procedure. A review and analysis of the equipment and techniques provides a better understanding of this effective technique.
The effect of dobutamine on blood flow of free tissue transfer flaps during head and neck reconstructive surgery*
Authors: Scholz A. , Pugh S. , Fardy M. , Shafik M. , Hall J. E.
Published: September 2009

In view of the controversy over the use of inotropes in free tissue transfer surgery, we assessed the effect of different intra‐operative dobutamine infusion rates on blood flow in the anastomosed recipient artery. Twenty patients undergoing head and neck tumour resection and immediate reconstructive surgery with free tissue transfer were recruited. After completion of the microvascular anastomoses, patients received dobutamine infusions of 2, 4 and 6 μg.kg−1.min−1 in a randomised order. After steady state dobutamine concentration was achieved, mean and maximum blood flow in the arterial anastomosis was measured at each concentration, using the Medi‐Stim Butterfly Flowmeter system. Systemic haemodynamic parameters were simultaneously recorded using a pulse contour cardiac output system. Both mean and maximum blood flow increased significantly in the anastomosed artery at dobutamine infusions of 4 and 6 μg.kg−1.min−1 and this was accompanied by increased cardiac output. This may improve free flap perfusion.
A documented previous difficult tracheal intubation as a prognostic test for a subsequent difficult tracheal intubation in adults
Authors: Lundstrøm L. H. , Møller A. M. , Rosenstock C. , Astrup G. , Gätke M. R. , Wetterslev J ,   the Danish Anaesthesia Database
Published: September 2009

We investigated the diagnostic accuracy of a documented previous difficult tracheal intubation as a stand‐alone test for predicting a subsequent difficult intubation. Our assessment included patients from the Danish Anaesthesia Database who were scheduled for tracheal intubation by direct laryngoscopy. We used a four‐point scale to grade the tracheal intubation. A previous difficult intubation was defined according to the presence of a record documenting a difficult penultimate tracheal intubation‐score for the 15 499 patients anaesthetised more than once. Our assessment demonstrates that a documented history of previous difficult or failed intubation using direct laryngoscopy are strong predictors of a subsequent difficult or failed intubation and may identify 30% of these patients. Although previous investigators have reported predictive values that exceed our findings markedly, a documented previous difficult or failed tracheal intubation appears in everyday anaesthetic practice to be a strong predictor of a subsequent difficult tracheal intubation.
Impact of prior therapies on the relative efficacy of bortezomib compared with dexamethasone in patients with relapsed/refractory multiple myeloma
Authors: Vogl Dan T. , Stadtmauer Edward A. , Richardson Paul G. , Sonneveld Pieter , Schuster Michael W. , Irwin David , Facon Thierry , Harousseau Jean‐Luc , Boral Anthony , Neuwirth Rachel , Anderson Kenneth C.
Published: September 2009

This subgroup analysis of the phase III APEX (Assessment of Proteasome Inhibition for Extending Remissions) trial examined whether prior exposure to specific therapies affected the relative efficacy of bortezomib versus dexamethasone in relapsed/refractory myeloma. Time to progression and overall survival were superior with bortezomib in all subgroups, with no evidence of interaction between any prior therapies and assignment to study therapy. Patients with prior thalidomide exposure had worse outcomes overall, but neither prior thalidomide nor prior autologous stem cell transplantation affected the relative efficacy of bortezomib versus dexamethasone. These results confirm the superiority of bortezomib over dexamethasone, regardless of prior exposure to specific therapies (clinicaltrials.gov: NCT00048230).
Human embryonic stem cells secrete soluble factors that inhibit cancer cell growth
Authors: Giuffrida D. , Rogers I. M. , Nagy A. , Calogero A. E. , Brown T. J. , Casper R. F.
Published: September 2009

Objectives:  The aim of this study was to determine whether normal human embryonic stem cells (hESC) would secrete factors that arrest growth of human epithelial cancer cell lines.

Materials and methods:  Cell proliferation was examined using the MTT assay then haemocytometer cell counts. Staining with propidium iodide followed by flow cytometry was used to detect cell cycle stages. Heat denaturation and molecular fractionation experiments were also performed.

Results:  We found that hESC conditioned medium (hESC CM) inhibited SKOV‐3 and HEY cell proliferation. Similar results were also obtained when we used breast and prostate cancer cell lines, whereas little or no inhibitory effect was observed when human fibroblasts were tested. Moreover, a co‐culture model confirmed that inhibition of cancer cell proliferation is mediated by soluble factors produced by hESCs. We also determined that the proportion of cancer cells in G1 phase was increased by hESC CM treatment, accompanied by decrease in cells in S and G2/M phases, suggesting that the factors slow progression of cancer cells by cell cycle inhibition. Heat denaturation and molecular fractionation experiments indicated a low molecular weight thermostable factor was responsible for these properties.

Conclusions:  Our findings provide evidence that the human embryonic microenvironment contains soluble factor(s) that are capable of inhibiting growth of cancer cells, and that exposure to such factors may represent a new cancer treatment strategy.
Lower numbers of circulating natural killer T (NK T) cells in individuals with human T lymphotropic virus type 1 (HTLV-1) associated neurological disease
Authors: Ndhlovu L C , Snyder-Cappione J E , Carvalho K I , Leal F E , Loo C P , Bruno F R , Jha A R , Devita D , Hasenkrug A M , Barbosa H M R , Segurado A C , Nixon D F , Murphy E L , Kallas E G
Published: September 2009

Human T lymphotropic virus type 1 (HTLV-1) infects 10–20 million people worldwide. The majority of infected individuals are asymptomatic; however, approximately 3% develop the debilitating neurological disease HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). There is also currently no cure, vaccine or effective therapy for HTLV-1 infection, and the mechanisms for progression to HAM/TSP remain unclear. NK T cells are an immunoregulatory T cell subset whose frequencies and effector functions are associated critically with immunity against infectious diseases. We hypothesized that NK T cells are associated with HAM/TSP progression. We measured NK T cell frequencies and absolute numbers in individuals with HAM/TSP infection from two cohorts on two continents: São Paulo, Brazil and San Francisco, CA, USA, and found significantly lower levels when compared with healthy subjects and/or asymptomatic carriers. Also, the circulating NK T cell compartment in HAM/TSP subjects is comprised of significantly more CD4+ and fewer CD8+ cells than healthy controls. These findings suggest that lower numbers of circulating NK T cells and enrichment of the CD4+ NK T subset are associated with HTLV-1 disease progression.
The European carbon balance. Part 3: forests
Authors: LUYSSAERT S. , CIAIS P. , PIAO S. L. , SCHULZE E.‐D. , JUNG M. , ZAEHLE S. , SCHELHAAS M. J. , REICHSTEIN M. , CHURKINA G. , PAPALE D. , ABRIL G. , BEER C. , GRACE J. , LOUSTAU D. , MATTEUCCI G. , MAGNANI F. , NABUURS G. J. , VERBEECK H. , SULKAVA M. , Van Der WERF G. R. , JANSSENS I. A. ,   members of the CARBOEUROPE‐IP SYNTHESIS TEAM
Published: September 2009

We present a new synthesis, based on a suite of complementary approaches, of the primary production and carbon sink in forests of the 25 member states of the European Union (EU‐25) during 1990–2005. Upscaled terrestrial observations and model‐based approaches agree within 25% on the mean net primary production (NPP) of forests, i.e. 520±75 g C m−2 yr−1over a forest area of 1.32 × 106 km2to 1.55 × 106 km2(EU‐25). New estimates of the mean long‐term carbon forest sink (net biome production, NBP) of EU‐25 forests amounts 75±20 g C m−2 yr−1. The ratio of NBP to NPP is 0.15±0.05. Estimates of the fate of the carbon inputs via NPP in wood harvests, forest fires, losses to lakes and rivers and heterotrophic respiration remain uncertain, which explains the considerable uncertainty of NBP. Inventory‐based assessments and assumptions suggest that 29±15% of the NBP (i.e., 22 g C m−2 yr−1) is sequestered in the forest soil, but large uncertainty remains concerning the drivers and future of the soil organic carbon. The remaining 71±15% of the NBP (i.e., 53 g C m−2 yr−1) is realized as woody biomass increments. In the EU‐25, the relatively large forest NBP is thought to be the result of a sustained difference between NPP, which increased during the past decades, and carbon losses primarily by harvest and heterotrophic respiration, which increased less over the same period.
Presentation and comments on EU legislation related to food industries–environment interactions: sustainable development, and protection of nature and biodiversity – genetically modified organisms
Authors: Arvanitoyannis Ioannis S. , Choreftaki Stefania , Tserkezou Persefoni
Published: September 2009

The European Union (EU) legislation regarding sustainable development moves along two distinct lines: the impact of industries (food industries included) on the environment (release of gases and green house effect and the effect of cultivating genetically modified organisms (GMOs) on the environment. EU voted three communications [COM(2002)524, COM(2003)301, COM(2004)38] in an attempt to set an action plan based on technologies to manage pollution, by promoting less polluting and less resource‐intensive products and services and ways to manage resources more efficiently. As such environment‐friendly technologies pervade practically all economic activities and sectors it is anticipated that they will reduce effectively energy and resource consumption thereby creating fewer emissions and less waste. As regards the cultivation and/or importing of GMOs, EU legislation was based on two directives (E.U. 90/219/EEC, E.U. 2001/18/EC) and four regulations [Regulation (EC) No. 258/97, Regulation (EC) No. 1830/2003, Regulation (EC) No. 1830/2003 and Regulation (EC) No. 1946/2003]. The directives aimed at adopting measures for limited use of GM micro‐organisms, making the procedure for granting consent to the deliberate release and placing on the market of GMOs more efficient and more transparent, making GMO labelling compulsory and thereby enhancing GMOs traceability along the entire food chain.
Influence of the cavity‐size on the survival rate of proximal ART restorations in primary molars
Authors: KEMOLI ARTHUR MUSAKULU , Van AMERONGEN WILLEM EVERT
Published: September 2009

Aim.  To evaluate the influence of the size of proximal cavities on the survival rate of the atraumatic restorative treatment (ART) restorations.

Design.  A total of 804 children, aged 6–8 years, from a low socio‐economic community, with an ART restorable proximal carious lesion in their primary molars, participated. Over a 3‐week period, three ‘experienced’ and four ‘inexperienced’ operators randomly paired with four ‘experienced’ and four ‘inexperienced’ assistants, made the restorations at site using hand instruments. They randomly used Fuji IX, Ketac Molar Easymix and Ketac Molar Aplicap glass ionomer cements to restore the cavities, under randomly selected rubber dam and cotton roll isolation methods. The fillings were independently evaluated by nine trained and calibrated evaluators.

Results.  After 1 year, the survival rate of the fillings evaluated in the study was 44.8%. Irrespective of the other factors involved, restorations with the highest survival rate were of size between 2 and 3 mm (mesio‐distal, bucco‐lingual, and depth) or volumes 10.0–19.9 mm3 (Chi‐square, P = 0.002, KM mean survival of 345 days).

Conclusions.  While the survival rates for class II ART restorations were still low, the choice of medium‐sized proximal cavities gave better survival rates for this technique.