bluuebunny/crossref_metadata_2025 huggingface dataset:
Charged macroparticles over liquid helium
Authors: Dyugaev A. M. , Grigor'ev P. D. , Lebedeva E. V.
Published: December 2012

An analysis of properties of a plasma with macroparticles (dust plasma) at cryogenic temperatures led us to the need to account for the effects of helium condensation on these particles. Micrometer particles in the saturated helium vapor are coated with a film of liquid helium with the thickness of about 100 Å. This limits their electronic charge, since the helium film is weakly permeable to electrons. The exceptions are clusters of Cs, Rb and K, which are not wetted by helium.
Thermal conductivity and torsional oscillations of solid 4He
Authors: Brazhnikov M. Yu. , Zmeev D. E. , Golov A. I.
Published: December 2012

Polycrystalline samples of hcp 4He of molar volume Vm = 19.5 cm3 with small amount of 3He impurities were grown in an annular container by the blocked-capillary method. Three concentrations of 3He, x3, were studied: isotopically purified 4He with the estimated x3 < 10−10, commercial ‘well-grade’ helium with x3 ∼ 3·10−7 and a mixture with x3 = 2.5·10−6. Torsional oscillations at two frequencies, 132.5 and 853.6 Hz, and thermal conductivity were investigated before and after annealing. The solid helium under investigation was located not only in the annular container but also in the axial fill line inside two torsion rods and dummy bob of the double-frequency torsional oscillator. The analysis of the frequency shifts upon loading with helium and changing temperatures of different parts of the oscillator suggests that the three techniques probe the properties of solid helium in three different locations: the two different torsion modes respond to the changes of the shear modulus of solid helium in either of the two torsion rods while the thermal conductivity probes the phonon mean free path in solid helium inside the annular container. The temperature and width of the torsional anomaly increase with increasing frequency and x3. The phonon mean free path increases with increasing x3. Annealing typically resulted in an increased phonon mean free path but often in little change in the torsional oscillator response. While the magnitude of the torsional anomaly and phonon mean free path can be very different in different samples, no correlation was found between them.
Structural-phase transitions in solid nitrous oxide
Authors: Drobyshev A. , Aldiyarov A. , Korshikov E. , Sokolov D. , Kurnosov V.
Published: December 2012

Features of the transformations in cryocondensed samples of nitrous oxide under thermal cycling at temperatures near T = 40 K are studied. It is shown how the deformation and translational vibrational subsystems of the condensed state of nitrous oxide react to these transitions. Measured vibrational spectra of the samples and the amplitudes and positions of the absorption bands of the characteristic vibrations are used to determine the temperature and character of the thermally stimulated transitions in films of cryocondensed nitrous oxide. An analysis of these IR spectra indicates that the transition from the amorphous state of nitrous oxide to the crystalline state takes place in several stages that reflect the relaxation processes associated with particular vibrational modes of the nitrous oxide molecule. The differences in the transition temperatures are determined by the activation energies characteristic of these modes.
The influence of superfluidity on impurities condensation in liquid helium
Authors: Gordon E. B.
Published: December 2012

All major aspects of the influence of superfluidity in He II on the processes of condensation of impurities suspended in it have been analyzed. Particular attention is given to the recently discovered phenomenon of impurities coalescence catalysis by quantized vortices in superfluid helium. The presence of quantized vortices not only tremendously accelerates the condensation process for any substance introduced into liquid helium but also gives rise to a completely new product—long and thin nanowires. The role of local overheating, which accompanies coalescence of particles inside superfluid helium, in formation of morphology and structure of impurity–helium condensates, including molecular crystals containing stabilized active atoms, is elucidated.
Carrier multiplication in bulk indium nitride
Authors: Jensen S. A. , Versluis J. , Cánovas E. , Pijpers J. J. H. , Sellers I. R. , Bonn M.
Published: December 2012

Carrier multiplication (CM) is the process of generating multiple electron-hole pairs from one absorbed photon. Narrow-gap InN is a material that has been proposed for achieving efficient CM. We quantify the CM efficiency in bulk InN using terahertz time-domain spectroscopy. While the CM onset occurs at relatively low photon energies in InN (1.7 ± 0.2 eV), corresponding to 2.7 ± 0.3 times its bandgap, the excitation efficiency above the onset increases linearly with a slope of only ∼13%/Eg. Based on these numbers, the efficiency increase of an InN based photovoltaic device owing to CM is limited to maximum 1% point.
Enhanced electroluminescence performances by controlling the position of carbon nanotubes
Authors: Kim Jin-Young , Kim Hoonbae , Jung Donggeun , Yu SeGi
Published: December 2012

Alternating current driven powder electroluminescence (EL) devices with single-walled carbon nanotubes (SWCNTs) were fabricated to utilize the field enhancement by controlling the position of SWCNTs. The SWCNT conditions, which could lead to increased EL performance, were optimized by examining the characteristics of EL devices after controlling the length of the SWCNTs, where the SWCNT layer was positioned at the interface between the dielectric and emitting layers. The EL device with a short SWCNT layer for a crushing time of 20 min exhibited the highest EL performance of the samples examined. In addition, SWCNTs with the optimized SWCNT condition were inserted at various interfaces to determine the effective position of the SWCNT layer in the EL device. The highest EL performance, such as a 51% and 65% increase in luminance and efficiency, respectively, was achieved by inserting SWCNTs at the interface between the dielectric and emitting layers together with SWCNTs between the emitting layer and bottom electrode. Large increase in EL performance was attributed to the field enhancement by short SWCNTs, leading to increased charge carrier tunneling.
Stable fracture of a malleable Zr-based bulk metallic glass
Authors: Sun B. A. , Tan J. , Pauly S. , Kühn U. , Eckert J.
Published: December 2012

We report a stable fracture phenomenon during the compression of a malleable Zr-based bulk metallic glass. In the process, the shear band along which the sample fails is constrained by the machine crosshead, thus causing a slow release of the stress and the elastic energy by small steps in the stress-strain curve. A novel and unique fishbone-like pattern was observed on the fracture surface after the final rupture instead of the typical vein-like pattern usually found upon catastrophic failure for metallic glasses. The formation of this pattern might be a result of the modest temperature rise during failure and the frustration of the meniscus instability in the crack tip due to stress redistribution in the constraint. This fracture behavior, where the crack propagation is at a much lower speed and the elastic energy is released in a stable way, might be suitable for studying the crack propagation process and the fracture mechanism in metallic glasses.
Ferromagnetism in Li doped ZnO nanoparticles: The role of interstitial Li
Authors: Ullah Awan Saif , Hasanain S. K. , Bertino Massimo F. , Hassnain Jaffari G.
Published: December 2012

ZnO nanoparticles doped with Li (Zn1−yLiyO, y ≤ 0.1) have been investigated with emphasis on the correlation between their magnetic, electronic, and structural properties. In particular, defects such as interstitial Li and Zn atoms, substitutional Li atoms, and oxygen vacancies have been identified by X-ray photoelectron spectroscopy (XPS) and their respective roles in stabilization of the magnetic moment are discussed. X-ray diffraction (XRD) and XPS give clear evidence of Li presence at both substitutional and interstitial sites. XPS studies further show that the amount of substitutional Li defects (Lizn) and interstitial Li defects (Lii) vary non-monotonically with the Li concentration, with the Lii defects being noticeably high for the y = 0.02, 0.08, and 0.10 concentrations, in agreement with the XRD results. Magnetization studies show room temperature ferromagnetism in these nanoparticles with the moment being largest for the particles with high concentration of interstitial lithium and vice versa. Both interstitial Zn (Zni) defects and Zn-O bonds were determined from the Zn LMM Auger peaks; however, the variation of these with Li concentrations was not large. Oxygen vacancies (Vo) concentrations are estimated to be relatively constant over the entire Li concentration range. We relate the Lii and Zni defects to the formation and stabilization of Zn vacancies and thus stabilizing the p-type ferromagnetism predicted for cation (zinc) vacancy in the ZnO type oxides.
Translocation through environments with time dependent mobility
Authors: Cohen Jack A. , Chaudhuri Abhishek , Golestanian Ramin
Published: December 2012

We consider single particle and polymer translocation where the frictional properties experienced from the environment are changing in time. This work is motivated by the interesting frequency responsive behaviour observed when a polymer is passing through a pore with an oscillating width. In order to explain this better we construct general diffusive and non-diffusive frequency response of the gain in translocation time for a single particle in changing environments and look at some specific variations. For two state confinement, where the particle either has constant drift velocity or is stationary, we find exact expressions for both the diffusive and non-diffusive gain. We then apply this approach to polymer translocation under constant forcing through a pore with a sinusoidally varying width. We find good agreement for small polymers at low frequency oscillation with deviations occurring at longer lengths and higher frequencies. Unlike periodic forcing of a single particle at constant mobility, constant forcing with time dependent mobility is amenable to exact solution through manipulation of the Fokker-Planck equation.
Optimization of Nb2O5/Ag/Nb2O5 multilayers as transparent composite electrode on flexible substrate with high figure of merit
Authors: Dhar Aritra , Alford T. L.
Published: December 2012

Different multilayer structures of Nb2O5/Ag/Nb2O5 have been deposited onto flexible substrates by sputtering at room temperature to develop an indium free transparent composite electrode. The effect of Ag thickness on the electrical and optical properties of the multilayer stack has been studied in accordance with the Ag morphology. The critical thickness of Ag to form a continuous conducting layer is found to be 9.5 nm. A new conduction mechanism has been proposed to describe the conduction before and after the critical thickness. The effective Hall resistivity of the optimized films is as low as 6.44 × 10−5 Ω-cm with a carrier concentration and mobility of 7.4 × 1021 cm−3 and 13.1 cm2 /V-s, respectively, at the critical Ag layer thickness. The multilayer stack has been optimized to obtain a sheet resistance of 7.2 Ω/sq and an average optical transmittance of 86% at 550 nm without any substrate heating or post-annealing process. The Haacke figure of merit (FOM) has been calculated for the films, and the multilayer with a 9.5 nm thick Ag layer has the highest FOM at 31.5 × 10-3 Ω−1, which is one of the highest FOM values reported for TCE deposited at room temperature on a flexible substrate.
Rovibrational levels of helium hydride ion
Authors: Pachucki Krzysztof , Komasa Jacek
Published: December 2012

Dissociation energy (D0) of rovibrational levels of 4HeH+ has been predicted theoretically to the accuracy of the order of 0.01 cm−1. The calculations take into account adiabatic and nonadiabatic corrections as well as relativistic and quantum electrodynamics effects. For the ground rovibrational level D0 = 14 874.215(10) cm−1 and it differs by several tens of the inverse centimeter from previous theoretical estimations. For a collection of about 50 transition energies measured between dipole connected levels the difference between theory and experiment is of the order of hundredths of cm−1 or less.
Determination of optical properties of percolated nanostructures using an optical resonator system
Authors: Sukmanowski J. , Battie Y. , Royer F. X. , En Naciri A.
Published: December 2012

In this work, methods are introduced to the determination of optical properties of thin silver films and nanostructures. We present an optical resonant system consisting of a mirror, a transparent layer and a thin silver film. The layer sequences and the nanostructure of the thin films are investigated by optical methods consist of reflectance measurements. The structures are analyzed by atomic force microscopy and scanning electron microscopy. The optical properties are determined by modeling the reflectance data. We have found that the growth mechanisms of the silver layer are correlated to its optical properties. It also found that temperature treatments produce isolated particles with a narrow plasmon resonance.
Investigation of polarization effects in the gramicidin A channel from ab initio molecular dynamics simulations
Authors: Timko Jeff , Kuyucak Serdar
Published: December 2012

Polarization is an important component of molecular interactions and is expected to play a particularly significant role in inhomogeneous environments such as pores and interfaces. Here we investigate the effects of polarization in the gramicidin A ion channel by performing quantum mechanics/molecular mechanics molecular dynamics (MD) simulations and comparing the results with those obtained from classical MD simulations with non-polarizable force fields. We consider the dipole moments of backbone carbonyl groups and channel water molecules as well as a number of structural quantities of interest. The ab initio results show that the dipole moments of the carbonyl groups and water molecules are highly sensitive to the hydrogen bonds (H-bonds) they participate in. In the absence of a K+ ion, water molecules in the channel are quite mobile, making the H-bond network highly dynamic. A central K+ ion acts as an anchor for the channel waters, stabilizing the H-bond network and thereby increasing their average dipole moments. In contrast, the K+ ion has little effect on the dipole moments of the neighboring carbonyl groups. The weakness of the ion-peptide interactions helps to explain the near diffusion-rate conductance of K+ ions through the channel. We also address the sampling issue in relatively short ab initioMD simulations. Results obtained from a continuous 20 ps ab initio MD simulation are compared with those generated by sampling ten windows from a much longer classical MD simulation and running each window for 2 ps with ab initio MD. Both methods yield similar results for a number of quantities of interest, indicating that fluctuations are fast enough to justify the short ab initio MD simulations.
Metastable hydronium ions in UV-irradiated ice
Authors: Moon Eui-Seong , Kang Heon
Published: December 2012

We show that the irradiation of UV light (10−11 eV) onto an ice film produces metastable hydronium (H3O+) ions in the ice at low temperatures (53–140 K). Evidence of the presence of metastable hydronium ions was obtained by experiments involving adsorption of methylamine onto UV-irradiated ice films and hydrogen-deuterium (H/D) isotopic exchange reaction. The methylamine adsorption experiments showed that photogenerated H3O+ species transferred a proton to the methylamine arriving at the ice surface, thus producing the methyl ammonium ion, which was detected by low energy sputtering method. The H3O+ species induced the H/D exchange of water, which was monitored through the detection of water isotopomers on the surface by using the Cs+ reactive ion scattering method. Thermal and temporal stabilities of H3O+ and its proton migration activity were examined. The lifetime of the hydronium ions in the amorphized ice was greater than 1 h at ∼53 K and decreased to ∼5 min at 140 K. Interestingly, a small portion of hydronium ions survived for an extraordinarily long time in the ice, even at 140 K. The average migration distance of protons released from H3O+ in the ice was estimated to be about two water molecules at ∼54 K and about six molecules at 100 K. These results indicate that UV-generated hydronium ions can be efficiently stabilized in low-temperature ice. Such metastable hydronium ions may play a significant role in the acid-base chemistry of ice particles in interstellar clouds.
Interaction of a planar shock wave with a dense particle curtain: Modeling and experiments
Authors: Ling Y. , Wagner J. L. , Beresh S. J. , Kearney S. P. , Balachandar S.
Published: December 2012

The interaction of a planar shock wave with a dense particle curtain is investigated through modeling and experiments. The physics in the interaction between a shock wave with a dense gas-particle mixture is markedly differently from that with a dilute mixture. Following the passage of the shock wave, the dense particle curtain expands rapidly as it propagates downstream and pressures equilibrate throughout the flow field. In the simulations, the particles are viewed as point-particles and are traced in a Lagrangian framework. A physics-based model is then developed to account for interphase coupling. Compared to the standard drag law, four major improvements are made in the present interphase coupling model to take into account: (1) unsteady force contributions to particle force; (2) effect of compressibility on hydrodynamic forces; (3) effect of particle volume fraction on hydrodynamic forces; (4) effect of inter-particle collision. The complex behavior of the dense particle curtain is due to the interplay between two-way coupling, finite particle inertia, and unsteady forces. Incorporation of these effects through significant modeling improvements is essential for the simulation results to agree well with the experimental data. As a result of the large pressure gradient inside the particle curtain, the unsteady forces remain significant for a long time compared to the quasi-steady force and greatly influence the particle curtain motion.
Studying DNA translocation in nanocapillaries using single molecule fluorescence
Authors: Thacker Vivek V. , Ghosal Sandip , Hernández-Ainsa Silvia , Bell Nicholas A. W. , Keyser Ulrich F.
Published: December 2012

We demonstrate simultaneous measurements of DNA translocation into glass nanopores using ionic current detection and fluorescent imaging. We verify the correspondence between the passage of a single DNA molecule through the nanopore and the accompanying characteristic ionic current blockage. By tracking the motion of individual DNA molecules in the nanocapillary perpendicular to the optical axis and using a model, we can extract an effective mobility constant for DNA in our geometry under high electric fields.
Cell electroporation chip using multiple electric field zones in a single channel
Authors: Kim Min-Ji , Kim Taeyoon , Cho Young-Ho
Published: December 2012

We present cell electroporation chip using a single channel with multiple electric field, E, zones. The present chip, where multiple E zones are generated by a pair of external electrodes across a stepwise single channel, provides the optimal E conditions for stable cell electroporation with high viability in a single experiment. The optimal E for both H23 and A549 cells was 0.4 kV/cm with the maximum percentage of the viable and electroporated cells of 51.4 ± 3.0% and 26.6 ± 0.7%, respectively. The present cell electroporation chip has potential for use in integrated cell chips to find the optimal E conditions for the electroporation study.
Communication: Electron impact ionization of binary H2O/X clusters in helium nanodroplets: An ab initio perspective
Authors: Shepperson Benjamin , Liu Jun , Ellis Andrew M. , Yang Shengfu
Published: December 2012

In a recent experiment (H2O)n/Xm binary clusters (where X = Ar, N2, CO, CO2, and several other molecules) were formed in superfluid helium nanodroplets and investigated by electron impact mass spectrometry [Liu et al., Phys. Chem. Chem. Phys. 13, 13920 (2011)10.1039/c1cp20653b]. The addition of dopant X was found to affect the branching ratio between H3O+(H2O)n and (H2O)+n+2 formation. Specifically, the addition of CO increased the proportion of protonated water cluster ions, whereas dopants such as Ar, N2, and CO2, had the opposite effect. In this work ab initio calculations have been performed on [X(H2O)2]+ ions, where X = Ar, N2, CO, and CO2, to try and explain this distinct behavior. CO is found to be unique in that it forms a HOCO-H3O+ unit in the most stable cationic complexes where the binding between HO and CO is stronger than that between H3O+ and OH. Thus, on purely energetic grounds, loss of HOCO rather than CO should be the preferred fragmentation process. No comparable chemistry occurs when X = Ar, N2, or CO2 and so the co-dopant requires less energy to depart than OH. The calculations therefore account for the experimental observations and provide evidence that HOCO formation is induced in helium droplets containing (H2O)n clusters and co-doped with CO when subject to electron impact ionization.
The ebbs and flows of changing acute bed capacity delays
Authors: Zeitz Kathryn M. , Carter Libby , Robinson Craig
Published: December 2012

Objective. This case study provides a summary of changes in acute hospital bed delays that have occurred over a 4-year period as identified through a Capacity Audit process. Background. Royal Adelaide Hospital (RAH) designed a Capacity Audit process and tool that provides a systematic method to evaluate factors limiting access to inpatient bed capacity. The aim of the audit is to improve understanding of bed capacity by identifying key causes of delay for hospital inpatients and quantify the most frequent causes of blocked bed capacity. This can then be used to underpin targeted improvement work. The Capacity Audit has been undertaken at the RAH over three cycles. Method. The Capacity Audit involves a survey of every open and staffed bed, identifying how the bed is being used: for acute care or treatment, if there was a delay to the patient for discharge, or if the bed was unavailable. The first and second cycle of the audit (2007–2008) involved a twice-daily survey over a 2-week period and the third audit cycle in 2010 occurred once daily for 1 week. Results. On average, 620 beds were surveyed daily with an audit compliance rate ranging from 85–97%. This process has revealed almost 75% of beds are used positively for care. Of the remaining 25% of hidden capacity identified, non-clinical discharge delays account for 10% of total beds surveyed. Waiting for post-acute beds has consistently remained the main cause of acute bed delay. Conclusion. The Capacity Audit process and tool has been used to track progress, trends and change resulting from service improvement efforts, and to provide the evidence to commence strategies to reduce the hidden capacity issues. This case study has shown that whilst overall bed stock usage for positive care has not changed significantly there are various ebbs and flows over time in relation to the reasons for bed delays.
Deligne’s category \underline{𝑅𝑒}𝑝(𝐺𝐿_{𝛿}) and representations of general linear supergroups
Authors: Comes Jonathan , Wilson Benjamin
Published: December 2012

We classify indecomposable summands of mixed tensor powers of the natural representation for the general linear supergroup up to isomorphism. We also give a formula for the characters of these summands in terms of composite supersymmetric Schur polynomials, and give a method for decomposing their tensor products. Along the way, we describe indecomposable objects inRe_p⁡(GLδ)\underline {\operatorname {Re}}\!\operatorname {p}(GL_\delta )and explain how to decompose their tensor products.
Direct interactions between the coiled-coil tip of DksA and the trigger loop of RNA polymerase mediate transcriptional regulation
Authors: Lennon Christopher W. , Ross Wilma , Martin-Tumasz Stephen , Toulokhonov Innokenti , Vrentas Catherine E. , Rutherford Steven T. , Lee Jeong-Hyun , Butcher Samuel E. , Gourse Richard L.
Published: December 2012

Escherichiacoli DksA is a transcription factor that binds to RNA polymerase (RNAP) without binding to DNA, destabilizing RNAP–promoter interactions, sensitizing RNAP to the global regulator ppGpp, and regulating transcription of several hundred target genes, including those encoding rRNA. Previously, we described promoter sequences and kinetic properties that account for DksA's promoter specificity, but how DksA exerts its effects on RNAP has remained unclear. To better understand DksA's mechanism of action, we incorporated benzoyl-phenylalanine at specific positions in DksA and mapped its cross-links to RNAP, constraining computational docking of the two proteins. The resulting evidence-based model of the DksA–RNAP complex as well as additional genetic and biochemical approaches confirmed that DksA binds to the RNAP secondary channel, defined the orientation of DksA in the channel, and predicted a network of DksA interactions with RNAP that includes the rim helices and the mobile trigger loop (TL) domain. Engineered cysteine substitutions in the TL and DksA coiled-coil tip generated a disulfide bond between them, and the interacting residues were absolutely required for DksA function. We suggest that DksA traps the TL in a conformation that destabilizes promoter complexes, an interaction explaining the requirement for the DksA tip and its effects on transcription.
Inducing RNAi in C. elegans by Feeding with dsRNA-expressing E. coli
Authors: Hammell Christopher M. , Hannon Gregory J.
Published: December 2012

Owing to the relative ease and high-throughput nature of ingestion-mediated RNAi, the feeding of engineered Escherichia coli to wild-type and mutant Caenorhabditis elegans has developed into the most productive and common method to probe the functions of C. elegans genes. This protocol includes two variations of RNAi by feeding: one in which L1 larvae are fed dsRNA-expressing E. coli in liquid culture (commonly used to score effects of RNAi on postembryonic larval development) and another involving feeding of late larval- or adult-staged animals on standard solid medium culture plates.
Liver Tumor Preparation in Mice
Authors: Jain Rakesh K. , Munn Lance L. , Fukumura Dai
Published: December 2012

The liver is the most common site for distant metastasis of colorectal carcinomas. In this protocol, a liver tumor metastasis model is prepared by performing a splenic injection of tumor cells in mice. This model can be used to study the effect of host–tumor interactions on tumor biology and therapeutic response.
Introduction of an N‐acetylcysteine weight‐based dosing chart reduces prescription errors in the treatment of paracetamol poisoning
Authors: McIntyre Shona , McD Taylor David , Greene Shaun
Published: December 2012

Objective

Under‐ or overdosing of N‐acetylcysteine (NAC), when used to treat paracetamol toxicity, is associated with significant morbidity and mortality. This study evaluated the effect of a weight‐based dosing chart (WBDC) introduced to decrease NAC prescription errors.

Methods

We undertook a pre‐ and post‐intervention trial in a single ED. The intervention (the NAC WBDC) was introduced in January 2011 and publicised by posters and presentations at medical handovers and education sessions. ED staff were not aware that use of the WBDC was to be evaluated. Data were collected using a retrospective explicit medical record review by a single investigator. The study end‐point was the proportion of NAC prescriptions with errors.

Results

The 81 and 42 patients enrolled in the pre‐ and post‐intervention periods, respectively, did not differ in age, sex or weight (P > 0.05). Post‐intervention, there were significant reductions in prescription errors of fluid type/volume (50.6% vs 4.8%, P < 0.001), NAC dosage (13.6% vs 0.0%, P = 0.01) and infusion rate (11.1% vs 0.0%, P = 0.03). The proportion of prescriptions with any errors also decreased (56.8% vs 14.3%, P < 0.001). However, there were no improvements in the documentation of patient weight (65.4% vs 64.3%, respectively, P = 0.90) or the proportion of incomplete prescriptions (4.9% vs 11.9%, P = 0.16).

Conclusion

The introduction of a WBDC did not produce a clinically significant reduction in major NAC prescription error rates (as pre‐defined in this study); however, there was a clear trend towards a reduction. The WBDC significantly reduced total and minor NAC prescription error rates.
Factors affecting length of stay for women presenting with early pregnancy complications to a public hospital emergency department
Authors: Wattimena Jeany , Pelosi Marilena , Cheney Kate , Green Timothy , Black Kirsten I
Published: December 2012

Objective

This study aimed to determine factors associated with length of stay (LOS) for women presenting with early pregnancy complications to a public hospital ED. In particular, we sought to investigate the impact the involvement of the Clinical Midwife Consultant (CMC), specialising in early pregnancy care, had on the ED LOS.

Methods

We undertook a retrospective cohort study of women less than 20 weeks pregnant who presented between August 2008 and December 2010 with early pregnancy complications to the ED of the Royal Prince Alfred Hospital in Sydney, Australia and who were then discharged. The main outcome measured was LOS. We performed logistic regression analysis to identify factors significantly associated with this outcome.

Results

Data were available for 1739 women. Involvement of the CMC reduced LOS and patients were significantly more likely to be discharged within 4 h or less (OR = 0.47, 95% CI = 0.37–0.60). The factors that increased LOS to over 4 h were arrival after hours (OR = 2.09, 95% CI = 1.66–2.63), being triaged as category 1 to 3 (OR = 1.36, 95% CI = 1.11–1.67) and requiring an ultrasound assessment (OR = 2.44, 95% CI = 1.81–3.28).

Conclusions

This study was able to show factors significantly associated with ED LOS, many of which are not modifiable. The involvement of the CMC reduced LOS, whereas requiring an ultrasound assessment increased LOS. Thus, improvement could be achieved by greater access to a CMC and more rapid access to ultrasound services.
Impact of gadoxetic acid (Gd‐EOB‐DTPA)‐enhanced magnetic resonance on the non‐invasive diagnosis of small hepatocellular carcinoma: a prospective study
Authors: Granito A. , Galassi M. , Piscaglia F. , Romanini L. , Lucidi V. , Renzulli M. , Borghi A. , Grazioli L. , Golfieri R. , Bolondi L.
Published: December 2012

Background

Gadoxetic acid (Gd‐EOB‐DTPA) is a ‘hepatocyte‐specific’ contrast agent for magnetic resonance (MR) in both the vascular and the hepatobiliary phases.

Aim

To evaluate the contribution of the hepatobiliary phase of Gd‐EOB‐DTPA MR in the diagnosis of small hepatocellular carcinoma (HCC) in cirrhotic patients under surveillance.

Methods

Between 2008 and 2011, 48 consecutive small (10–30 mm) liver nodules were detected in 33 patients, who prospectively underwent contrast‐enhanced ultrasound (CEUS), Gd‐EOB‐DTPA‐enhanced MR and helical‐computed tomography (CT) in a blind study. The diagnosis of HCC was established according to AASLD 2005 criteria.

Results

Of the 48 nodules, 38 (79%) were diagnosed as HCC, 24 (63%) of them based on AASLD non‐invasive criteria, 11 diagnosed at histology and 3 during follow‐up. The typical vascular pattern (arterial hypervascularisation and venous/late washout) was detected in 30 (79%) HCC nodules by MR, in 22 (58%) by CT and in 17 (45%) by CEUS. Hypointensity during the MR hepatobiliary phase was observed in all HCC nodules and in 3 nonmalignant nodules (sensitivity 100%, specificity 70%, positive predictive value 93%, negative predictive value 100%, positive likelihood ratio 3.33, negative likelihood ratio 0). Eight (21%) of the 38 HCC nodules, 7 of which lacked the typical vascular features at any of the imaging modalities, showed washout in the portal/venous phase and hypointensity in the hepatobiliary phase at MRI, while this pattern was not detected in any nonmalignant lesion.

Conclusions

Gadoxetic acid magnetic resonance may enhance the sensitivity of the non‐invasive diagnosis of small hepatocellular carcinoma nodules in cirrhotic patients under surveillance. Double hypointensity in the portal/venous and hepatobiliary phases could be considered a new magnetic resonance pattern, highly suggestive of hypovascular hepatocellular carcinoma.
Resolution of hyphaema following intracameral injection of tenecteplase in a Stock Horse
Authors: Rendle DI , Hughes KJ
Published: December 2012

Intracameral injection of tissue plasminogen activator has been suggested as a means of hastening the clearance of blood from the anterior chamber and reducing the risk of synechia and fibrotic membrane formation in horses with hyphaema. The following report describes a case of ocular trauma in which intracameral injection of tenecteplase (TNK), a new‐generation plasminogen activator, resulted in rapid resolution of hyphaema and successful outcome. However, a large dose (1 mg) was administered and may have been associated with retinopathy and keratopathy. TNK may be an effective treatment for equine hyphaema and further controlled clinical or experimental studies are required to determine its efficacy and safety profiles.
Design, Synthesis and Structure–Activity Relationship of New Arginine Vasopressin Analogues Containing Proline Derivatives in Position 2
Authors: Kwiatkowska Anna , Lewandowska Monika , Borovičková Lenka , Slaninová Jiřina , Lammek Bernard , Prahl Adam
Published: December 2012

In this study, we present the synthesis and pharmacological properties of new analogues of arginine vasopressin modified in the N‐terminal part of the molecule with proline derivatives: indoline‐2‐carboxylic acid (Ica) and (2S,4R)‐4‐(naphthalene‐2‐ylmethyl)pyrrolidine‐2‐carboxylic acid. All the peptides were tested for pressor, antidiuretic and in vitro uterotonic activities. We also determined their binding affinity to the human oxytocin receptor. The Ica2 substitution resulted in two moderately potent and selective antioxytocic agents: [Mpa1, Ica2, D‐Arg8]VP and [Mpa1,Ica2,Val4,D‐Arg8]VP (pA2 = 7.09 and 7.50, respectively). On the other hand, peptides modified with (2S,4R)‐4‐(naphthalene‐2‐ylmethyl)pyrrolidine‐2‐carboxylic acid, apart from their moderate antioxytocic activity, turned out to be weak antagonists of the pressor response to arginine vasopressin. The results of this study provide useful information about the structure–activity relationship of arginine vasopressin analogues and can help to design compounds with desired biological properties.
Effects of acidic phospholipids on antiganglioside antibodies in Guillain–Barré syndrome: Role of the disialosyl residue
Authors: Yamada Minako H. , Ueda Masami , Tsuji Shoji , Kusunoki Susumu
Published: December 2012

Objectives

The activities of anti‐GM1 immunoglobulin G (IgG) antibodies in Guillain–Barré syndrome (GBS) are increased when a mixture of acidic phospholipids, such as phosphatidic acid (PA) and the ganglioside GM1, is used as an antigen in an enzyme‐linked immunosorbent assay (ELISA). In contrast, no obvious enhancing effect is seen on the activities of anti‐GQ1b antibodies in Fisher syndrome. The cause of these different results remains to be determined. We investigated whether it is caused by the difference in the pathogens of the preceding infections or by that in the physicochemical properties of GM1 and GQ1b.

Methods

The effects of the phospholipid on the antibody activities in ELISA were compared between the cases preceded by respiratory infections and those by gastrointestinal infections. We examined the effects of the phospholipids on anti‐GD1b IgG antibodies and compared the effects on GD1b‐specific antibodies and those on Gal‐GalNAc epitope‐specific antibodies.

Results

The effects of the phospholipids on the average of the antibody activities, either anti‐GM1 or anti‐GQ1b antibody, did not differ between patients with antecedent gastrointestinal infections and those with respiratory infections. The anti‐GD1b IgG activity in GBS patients with anti‐Gal‐GalNAc specificity increased when a mixture of GD1b and a phospholipid, such as PA, was an antigen; whereas the activity of monospecific anti‐GD1b IgG did not increase.

Conclusions

The enhancing effect of such a phospholipid as PA appears not to be a result of the presence of a particular phospholipid within the pathogen for the antecedent infection. It might depend on the presence of a negatively charged disialosyl residue in the ganglioside antigen.
Visceral adiposity index is highly associated with adiponectin values and glycaemic disturbances
Authors: Al‐Daghri Nasser M. , Al‐Attas Omar S. , Alokail Majed S. , Alkharfy Khalid M. , Charalampidis Paris , Livadas Sarantis , Kollias Anastasios , Sabico Shaun Louie , Chrousos George P.
Published: December 2012

Background

Visceral Adiposity Index (VAI) is a gender‐specific mathematical index estimated with the use of simple anthropometric (body mass index and waist circumference) and biochemical (triglycerides and high density lipoprotein cholesterol) parameters. Recent studies have shown that VAI reflects accurately the degree of visceral adiposity and insulin resistance. However, up to now, VAI has not been evaluated if it correlates with carbohydrate metabolism disorders, as well as with adipokine secretion from the fat mass.

Methods

In a cohort of 308 out of 414 adult Saudi subjects screened for the study, detailed personal medical history, anthropometrics and metabolic/hormonal profiles were obtained. Additionally, the circulating concentrations of several circulating adipokines, namely adiponectin, leptin, tumour necrosis factor‐α (TNF‐α) and resistin, were measured.

Results

Stepwise multivariate analysis showed that VAI was the sole determinant of adiponectin levels (R2 = 0·07, beta ± SE: −0·25 ± 0·05), while BMI and female gender predicted leptin levels (R2 = 0·26, 0·10 ± 0·01 and 0·61 ± 0·15, respectively). Furthermore, the presence of impaired fasting glucose (IFG)/diabetes was predicted only by age and VAI.

Conclusions

We report for the first time the direct relations of VAI with adipose tissue secretion, as well as with functional glycaemic disorders. Because VAI is estimated easily with data obtained in everyday practice, it could be used as an indirect index of adiponectin levels and the risk of impaired glucose metabolism.
Estimation of the Height of Complete Groundwater Drainage Above Mined Longwall Panels
Authors: Tammetta Paul
Published: December 2012

The height of complete groundwater drainage above subsided longwall panels (referred to as H) at underground mines is determined using a data base of hydraulic head measurements made with multiple devices down the depth profile at each of a number of sites worldwide. H is shown to be relatively independent of most parameters except the geometry of the mined void and the overburden thickness. An empirical equation linking H to these parameters is developed using hydraulic head data, and confirmed using an independent data base of ground movement. H is shown to be the same as the height of the zone of major ground movement above a panel. H for special cases (above longwall chain pillars, above pillar extraction panels, and underneath significant water bodies) is invariably smaller than H above center panel for ordinary cases. A new caving model, from a groundwater perspective, is proposed for continuously sheared longwall panels at ordinary locations. It removes complexity and reduces the uncertainty in estimating H. The derived equation for H applies to a variety of strata types.
Alchemy and Christianity in the Middle Ages
Authors: Matus Zachary A.
Published: December 2012

This essay discusses recent research in the study of medieval alchemy that bears upon its relationship to Christianity in the Latin West. Much of this scholarship has emerged from a renewed understanding of alchemy’s proto‐scientific character and its significant ties to the modern science of chemistry. The insistence that medieval alchemy’s primary aim was the study and manipulation of physical substances has encouraged a reappraisal of its religious aspects. This reappraisal surely begins with the admission that many medieval alchemical texts contain no religious elements at all. And for those that do, religiosity must be considered an outgrowth of both the preoccupation of alchemy with the material world as well as the religious cultures in which alchemical texts emerged.
Effect of grape variety on the evolution of sugars, hydroxymethylfurfural, polyphenols and antioxidant activity during grape must cooking
Authors: Tagliazucchi Davide , Verzelloni Elena , Helal Ahmed , Conte Angela
Published: December 2012

Grape must cooking is a traditional practice used for the production of foodstuff worldwide such as traditional balsamic vinegar. The aim of this work was to reveal the effect of grape variety on the evolution of the main chemical components in grape must during cooking. To this end, two grape must varieties (red Lambrusco and white Trebbiano grapes) were cooked and analysed. The monosaccharide concentration decreased because cooking resulting in the formation of 5‐hydroxymethylfurfural. At the end of cooking, the antioxidant activity and polyphenol concentration were higher and the 5‐hydroxymethylfurfural was lower in Lambrusco than in Trebbiano must. Additional changes involved degradation of monomeric anthocyanins resulting in the formation of the corresponding phenolic acids. From a health point of view, the high antioxidant activity and polyphenol concentration and the low 5‐hydroxymethylfurfural concentration make cooked red Lambrusco must a safer raw starting material for making traditional balsamic vinegar.
Physico‐mechanical evaluation of the aptitude of berries of red wine grape varieties to resist the compression in carbonic maceration vinification
Authors: Giacosa Simone , Torchio Fabrizio , Segade Susana Río , Gaiotti Federica , Tomasi Diego , Lovat Lorenzo , Vincenzi Simone , Rolle Luca
Published: December 2012

By texture analysis tests, the ability of berries to resist rupture under compression load during intracellular fermentation was studied for twenty‐three red wine grape varieties. The softest berries were associated with Ancellotta (1.72 N), Dolcetto (1.79 N), Gamay (2.26 N) and Schiava gentile (2.29 N) cultivars. The hardest berries corresponded to Franconia and Bonarda cultivars (4.02–4.03 N). High resistance to splitting was also detected for Grenache, Raboso, Marzemino, Negramaro, Montepulciano and Croatina cultivars (3.50–3.95 N). The differentiating power of the mechanical variables of the whole berry and skin was assessed by univariate and multivariate analysis. Relationships among the instrumental berry hardness and other physical and mechanical properties were also investigated. The results obtained suggest that the manufacture of carbonic macerated wines should be planned considering the berry hardness, and it represents a new variable that should be considered in selecting the most appropriate wine grape variety to elaborate these wines.
The imbalance of T helper 17/regulatory T cells and memory B cells during the early post‐transplantation period in peripheral blood of living donor liver transplantation recipients under calcineurin inhibitor‐based immunosuppression
Authors: Kim Hee Yeon , Cho Mi‐La , Jhun Joo Yeon , Byun Jae Kyeong , Kim Eun‐Kyung , Yim Ye Been , Chung Byung Ha , Yoon Seung Kew , Bae Si Hyun , Kim Dong Goo , Yang Chul Woo , Choi Jong Young
Published: December 2012

There is limited clinical research regarding the changes in peripheral lymphocyte subsets during the early post‐operative period of liver transplantation. Serial changes of T cells and B cells in living donor liver transplantation (LDLT) recipients during the early post‐transplantion period were prospectively investigated. From June 2010 to February 2011, 27 consecutive LDLT recipients were enrolled. Percentages of T helper type 1 (Th1; interferon‐γ‐producing), Th2 (interleukin‐4‐producing), Th17 (interleukin‐17‐producing), regulatory T (Treg; CD4+ CD25+ FoxP3+), memory B (CD19+ CD24hi CD38−) and mature B (CD19+ CD24int CD38int) cells were measured using fluorescence‐activated cell sorting. Patients were followed up for a median of 9·9 months (range 6·8−15·5 months) after transplantation. Serial monitoring of immunological profiles showed no significant suppression of Th1, Th2, Th17, mature B or memory B cells, whereas frequencies of Treg cells significantly decreased. Interleukin‐17 production by central and effector memory cells was not suppressed during the early post‐operative period. The continuous production of interleukin‐17 by the memory T cells may contribute to the persistence of Th17 cells. This prospective study demonstrated that current immunosuppression maintained the effector T or memory B cells during the early post‐transplantation period but significantly suppressed Treg cells. Serial immune monitoring may suggest clues for optimal or individualized immunosuppression during the early post‐operative period in clinical practice.
UNIVERSITY COMPETITION, GRADING STANDARDS, AND GRADE INFLATION
Authors: POPOV SERGEY V. , BERNHARDT DAN
Published: December 2012

We develop a model of strategic grade determination by universities distinguished by their distributions of student academic abilities. Universities choose grading standards to maximize the total wages of graduates, taking into account how the grading standards affect firms' productivity assessment and job placement. We identify conditions under which better universities set lower grading standards, exploiting the fact that firms cannot distinguish between “good” and “bad”“A’'s. In contrast, a social planner sets stricter standards at better universities. We show how increases in skilled jobs drive grade inflation, and determine when grading standards fall faster at better schools. (JEL I21)
BRAIN DRAIN IN GLOBALIZATION: A GENERAL EQUILIBRIUM ANALYSIS FROM THE SENDING COUNTRIES' PERSPECTIVE
Authors: MARCHIORI LUCA , SHEN I‐LING , DOCQUIER FRÉDÉRIC
Published: December 2012

According to the economic literature, high‐skilled emigration may either harm or benefit developing economies. Recent research highlighted several positive and negative channels through which the brain drain operates. This paper aims at evaluating the relative magnitudes of various brain drain channels and quantifying their global impact on migrants' sending countries. For this purpose, we develop a 10‐region general equilibrium model of the world economy characterized by overlapping‐generations dynamics. Our findings suggest that the short‐run impact of brain drain on resident human capital is extremely crucial, as it affects not only the number of high‐skilled workers available to domestic production, but also the sending economy's capacity to innovate/adopt modern technologies. This latter effect is particularly important in globalization, where capital investments are made in places with high production efficiencies. Hence, despite positive feedback effects, those countries facing prevalent high‐skilled emigration are the most candid victims to brain drain. (JEL F22, J24, O57)