bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Co doping on catalytic activity of small Pt clusters
Authors: Dhilip Kumar T. J. , Zhou Chenggang , Cheng Hansong , Forrey Robert C. , Balakrishnan N.
Published: March 2008

Platinum is the most widely used catalyst in fuel cell electrodes. Designing improved catalysts with low or no platinum content is one of the grand challenges in fuel cell research. Here, we investigate electronic structures of Pt4 and Pt3Co clusters and report a comparative study of adsorption of H2, O2, and CO molecules on the two clusters using density functional theory. The adsorption studies show that H2 undergoes dissociative chemisorption on the tetrahedral clusters in head on and side on approaches at Pt centers. O2 dissociation occurs primarily in three and four center coordinations and CO prefers to adsorb on Pt or Co atop atoms. The adsorption energy of O2 is found to be higher for the Co doped cluster. For CO, the Pt atop orientation is preferred for both Pt4 and Pt3Co tetrahedral clusters. Adsorption of CO molecule on tetrahedral Pt3Co in side on approach leads to isomerization to planar rhombus geometry. An analysis of Hirshfeld charge distribution shows that the clusters become more polarized after adsorption of the molecules.
Topological higher gauge theory: From BF to BFCG theory
Authors: Girelli F. , Pfeiffer H. , Popescu E. M.
Published: March 2008

We study generalizations of three- and four-dimensional BF theories in the context of higher gauge theory. First, we construct topological higher gauge theories as discrete state sum models and explain how they are related to the state sums of Yetter, Mackaay, and Porter. Under certain conditions, we can present their corresponding continuum counterparts in terms of classical Lagrangians. We then explain that two of these models are already familiar from the literature: the ΣΦEA model of three-dimensional gravity coupled to topological matter and also a four-dimensional model of BF theory coupled to topological matter.
Theoretical study of in-plane response of magnetic field sensor to magnetic beads in an in-plane homogeneous field
Authors: Damsgaard Christian Danvad , Hansen Mikkel Fougt
Published: March 2008

We present a systematic theoretical study of the average in-plane magnetic field on square and rectangular magnetic field sensors from a single magnetic bead and a monolayer of magnetic beads magnetized by an in-plane externally applied homogeneous magnetic field. General theoretical expressions are derived such that the sensor response and its dependence on the sensor size, spacer layer thickness, bead diameter, and bead susceptibility can easily be evaluated. The average magnetic field from a single bead close to the sensor shows a strong dependence on the position of the bead and a change of sign when the bead passes the edge of the sensor in the direction of the applied field. Analytical approximations are derived for the average field from a homogeneous monolayer of beads for beads much smaller than the sensor dimension and for a bead size chosen to minimize the position sensitivity of the sensor response. We discuss implications for the sensor design and give general guidelines for optimum choices of sensor dimension, spacer layer thickness, and bead diameter, as well as simple expressions for the average magnetic field from the beads. The usage of the general guidelines is exemplified in the design considerations for a sensor, which is fully covered by 100 beads and has a spacer layer thickness of 100 nm.
Nearfield surface enhanced spectroscopy using targeted nanoparticle deposition
Authors: Anderson Mark S.
Published: March 2008

Surface enhanced spectroscopy is demonstrated by depositing gold nanoparticles on a surface using an atomic force microscope. A modified dip pen nanolithography process is used to place particles directly on to a target. Near-field optical enhancement is demonstrated for Raman and infrared spectroscopies and is applicable for fluorescence spectroscopy. This approach provides localized, near-field spectroscopy with subdiffraction limit resolution and a general method for fabricating plasmonic device structures.
Temperature dependence of the frequency and noise of superconducting coplanar waveguide resonators
Authors: Kumar Shwetank , Gao Jiansong , Zmuidzinas Jonas , Mazin Benjamin A. , LeDuc Henry G. , Day Peter K.
Published: March 2008

We present measurements of the temperature and power dependence of the resonance frequency and frequency noise of superconducting niobium thin-film coplanar waveguide resonators carried out at temperatures well below the superconducting transition (Tc=9.2K). The noise decreases by nearly two orders of magnitude as the temperature is increased from 120to1200mK, while the variation of the resonance frequency with temperature over this range agrees well with the standard two-level system (TLS) model for amorphous dielectrics. These results support the hypothesis that TLSs are responsible for the noise in superconducting microresonators and have important implications for resonator applications such as qubits and photon detectors.
Quantification of energy dissipation for laterally oscillating microstructures
Authors: Bahukudumbi P. , Beskok Ali
Published: March 2008

Fluid film damping in laterally oscillating microstructures is investigated in the entire Knudsen regime and a wide Stokes number range using analytical and numerical results from Park et al. [“Rarefaction effects on shear driven oscillatory gas flows: A direct simulation Monte Carlo study in the entire Knudsen regime,” Phys. Fluids 16, 317 (2004)] and Hadjiconstantinou [“Oscillatory shear driven gas flows in the transition and free-molecular-flow regimes,” Phys. Fluids 17, 100611 (2005)]. An energy dissipation parameter per oscillation cycle that allows a consistent interpretation of the quality factor utilized in the design of microelectromechanical system devices is presented.
Doping efficiency, dopant location, and oxidation of Si nanocrystals
Authors: Pi X. D. , Gresback R. , Liptak R. W. , Campbell S. A. , Kortshagen U.
Published: March 2008

Gas-phase plasma-synthesized silicon nanocrystals (Si-NCs) are doped with boron (B) or phosphorous (P) during synthesis. The doping efficiency of B is smaller than that of P, consistent with the theoretical prediction of impurity formation energies. Despite vastly different synthesis conditions, the effect of doping on the photoluminescence (PL) of gas-phase-synthesized Si-NCs is qualitatively similar to that of Si-NCs doped during solid phase nucleation. Studies of oxidation-induced changes in PL and etching-induced changes in dopant concentration show that P resides at or near the Si-NC surface, while B is in the Si-NC cores. The oxidation of Si-NCs follows the Cabrera–Mott mechanism [N. Cabrera and N. F. Mott, Rep. Prog. Phys. 12, 163 (1948)].
Bilinear, trilinear forms, and exact solution of certain fourth order integrable difference equations
Authors: Sahadevan R. , Rajakumar S.
Published: March 2008

A systematic investigation of finding bilinear or trilinear representations of fourth order autonomous ordinary difference equation, x(n+4)=F(x(n),x(n+1),x(n+2),x(n+3)) or xn+4=F(xn,xn+1,xn+2,xn+3), is made. As an illustration, we consider fourth order symplectic integrable difference equations reported by [Capel and Sahadevan, Physica A 289, 86 (2001)] and derived their bilinear or trilinear forms. Also, it is shown that the obtained bilinear representations admit exact solution of rational form.
Magnetic field tuning of interface electronic properties in manganite-titanate junctions
Authors: Matsuno J. , Sawa A. , Kawasaki M. , Tokura Y.
Published: March 2008

We have investigated epitaxial Nd0.5Sr0.5MnO3∕SrTi0.9998Nb0.0002O3(110) (NSMO/Nb:STO) junctions wherein a metal-insulator transition can be induced by magnetic field in the NSMO layer. The NSMO/Nb:STO junctions show highly rectifying current density–voltage (J-V) characteristics, in accord with the conventional theory for a Schottky (or a p-n) diode. The forward bias J-V, as well as the reverse bias capacitance-voltage characteristics, has revealed a built-in potential of 0.8–0.9eV. In the reverse bias region, a large positive magnetocapacitance has been observed at 5 and 50K, suggesting that the effective carrier density of NSMO is modified by the magnetic field.
Interfacial electronic structure of SrTiO3∕SrRuO3 heterojuctions studied by in situ photoemission spectroscopy
Authors: Kumigashira H. , Minohara M. , Takizawa M. , Fujimori A. , Toyota D. , Ohkubo I. , Oshima M. , Lippmaa M. , Kawasaki M.
Published: March 2008

In situ photoemission spectroscopy (PES) has been performed on SrTiO3 (STO)∕SrRuO3 (SRO) bilayers to study the interfacial electronic structure of a SRO layer buried in STO. Using the interface (surface) sensitivity of PES measurements, the interface spectra of Ru 4d derived states near the Fermi level (EF) were extracted from the spectra of STO/SRO bilayers, as well as the surface spectra of SRO films. We found that the Ru 4d derived sharp peak at EF persists at the interface, while it smears out at the surface. These results suggest that the physical properties of SRO are maintained at the interface with STO.
Wearless scratch on NiTi shape memory alloy due to phase transformational shakedown
Authors: Feng Xi-Qiao , Qian Linmao , Yan Wenyi , Sun Qingping
Published: March 2008

Cyclic microscratch tests were performed to examine the scratching behavior of NiTi shape memory alloy. It shows a superior wear resistance within the temperature range of 22–120°C, but the corresponding physical mechanisms are different at low and high temperatures. We introduced the concept of phase transformational shakedown to interpret the wear-resistant behavior. At room temperature, a scratch groove may be caused by repeated scratching, but its depth stops increasing after a certain number of scratching cycles once the phase transformational shakedown state has been achieved. The groove will be self-healed upon heating as a result of the shape memory effect. At 60 and 120°C, however, no evident scratch groove is observed under the same load due to the pseudoelastic effect and the increase in the phase transition stress with temperature.
Zn
Cd
Se
∕
Zn
Cd
Mg
Se
quantum cascade electroluminescence
Authors: Franz Kale J. , Charles William O. , Shen Aidong , Hoffman Anthony J. , Tamargo Maria C. , Gmachl Claire
Published: March 2008

This letter reports electroluminescence emission from a ZnCdSe∕ZnCdMgSe quantum cascade (QC) structure. With a two-well QC active region design, the II-VI heterostructure was grown lattice matched on an InP substrate by molecular beam epitaxy. Deep etched mesas were electrically pumped at current densities up to 10kA∕cm2, producing optical emission centered near 4.8μm, in good agreement with the structure design. The light is predominantly TM polarized, confirming its intersubband origin. Electroluminescence was observed from 78to300K.
Bangkok Space, and Conditions of Possibility
Authors: King Ross
Published: March 2008

This is an essay on the ‘conditions of possibility’ (Kant) for thinking about the seemingly bizarre spaces of a grandly chaotic city. It is concerned with the possibility of distinctively different, contradictory (therefore incompatible) yet coexisting general modes of thinking—epistemes or discursive formations (Foucault)—and with the possible processes of their production. I begin with those spaces themselves and with their contested social production (Lefebvre), what they appear to show and what they seem to mask. Then, in the second part of the paper, the task is to explore the conditions that might underlie the remembering of many things and the forgetting of many things (Anderson), in the myriad decisions and actions that account for the production of such spaces. The third part is concerned with what these spaces might themselves tell us about deeper origins, the society itself, and its possible trajectory. A brief final part addresses the most problematic of issues: how is self-aware, self-critical discourse to arise in (against?) an episteme that eschews the articulation of criticism?
Scaling-up the Synthesis of 1-Butyl-3-methylimidazolium Chloride under Microwave Irradiation
Authors: Erdmenger Tina , Paulus Renzo M. , Hoogenboom Richard , Schubert Ulrich S.
Published: March 2008

Ionic liquids are considered to be ‘green’ solvents on account of their non-volatility and non-flammability – which are results of their negligible vapour pressures – as well as reusability. On the basis of ecological concerns, ionic liquids seem to be an attractive alternative to conventional volatile organic solvents. In the present work, the reaction conditions for the synthesis of 1-butyl-3-methylimidazolium chloride were optimized on a small scale (~2 mL, 10 mmol) using a single-mode microwave system. The conditions obtained were subsequently transferred to various microwave reactors, both batch and continuous flow, as well as mono-mode and multi-mode, for the direct scale-up of the synthesis from 0.01 to 1.15 mol.
Synthesis of 1,1,3,3-Tetraalkylisoindolines Using a Microwave-Assisted Grignard Reaction
Authors: Foitzik Richard C. , Bottle Steven E. , White Jonathan M. , Scammells Peter J.
Published: March 2008

1,1,3,3-Tetraalkylisoindolines are important intermediates in the preparation of stable nitroxides, such as 1,1,3,3-tetramethylisoindolin-2-oxyl, 1, and 1,1,3,3-tetraethylisoindolin-2-oxyl, 2. The limiting step in their preparation is the Grignard reaction between N-benzylphthalimide and the appropriate alkyl magnesium bromide, which typically proceeds in yields of ~28–40%. A microwave-assisted variation of this reaction has been optimized to give improved yields and reduced reaction times (45–60% and 2 h, respectively).
Antigen kinetics determines immune reactivity
Authors: Johansen Pål , Storni Tazio , Rettig Lorna , Qiu Zhiyong , Der-Sarkissian Ani , Smith Kent A. , Manolova Vania , Lang Karl S. , Senti Gabriela , Müllhaupt Beat , Gerlach Tilman , Speck Roberto F. , Bot Adrian , Kündig Thomas M.
Published: March 2008

A current paradigm in immunology is that the strength of T cell responses is governed by antigen dose, localization, and costimulatory signals. This study investigates the influence of antigen kinetics on CD8 T cell responses in mice. A fixed cumulative antigen dose was administered by different schedules to produce distinct dose-kinetics. Antigenic stimulation increasing exponentially over days was a stronger stimulus for CD8 T cells and antiviral immunity than a single dose or multiple dosing with daily equal doses. The same was observed for dendritic cell vaccination, with regard to T cell and anti-tumor responses, and for T cells stimulatedin vitro. In conclusion, stimulation kineticsper sewas shown to be a separate parameter of immunogenicity. These findings warrant a revision of current immunization models and have implications for vaccine development and immunotherapy.
Organic transistors manufactured using inkjet technology with subfemtoliter accuracy
Authors: Sekitani Tsuyoshi , Noguchi Yoshiaki , Zschieschang Ute , Klauk Hagen , Someya Takao
Published: March 2008

A major obstacle to the development of organic transistors for large-area sensor, display, and circuit applications is the fundamental compromise between manufacturing efficiency, transistor performance, and power consumption. In the past, improving the manufacturing efficiency through the use of printing techniques has inevitably resulted in significantly lower performance and increased power consumption, while attempts to improve performance or reduce power have led to higher process temperatures and increased manufacturing cost. Here, we lift this fundamental limitation by demonstrating subfemtoliter inkjet printing to define metal contacts with single-micrometer resolution on the surface of high-mobility organic semiconductors to create high-performance p-channel and n-channel transistors and low-power complementary circuits. The transistors employ an ultrathin low-temperature gate dielectric based on a self-assembled monolayer that allows transistors and circuits on rigid and flexible substrates to operate with very low voltages.
The editing enzyme ADAR1 and the mRNA surveillance protein hUpf1 interact in the cell nucleus
Authors: Agranat Lily , Raitskin Oleg , Sperling Joseph , Sperling Ruth
Published: March 2008

Posttranscriptional regulation is an important step in the regulation of gene expression. In this article, we show an unexpected connection between two proteins that participate in different processes of posttranscriptional regulation that ensures the production of functional mRNA molecules. Specifically, we show that the A-to-I RNA editing protein adenosine deaminase that acts on RNA 1 (ADAR1) and the human Upf1 (hUpf1) protein involved in RNA surveillance are found associated within nuclear RNA-splicing complexes. A potential functional role for this association was revealed by RNAi-mediated down-regulation of ADAR1, which was accompanied by up-regulation of a number of genes previously shown to undergo A-to-I editing in
Alu
repeats and to be down-regulated by hUpf1. This study suggests a regulatory pathway by a combination of ADAR1 A-to-I editing enzyme and RNA degradation presumably with the aid of hUpf1.
Osteocalcin differentially regulates β cell and adipocyte gene expression and affects the development of metabolic diseases in wild-type mice
Authors: Ferron Mathieu , Hinoi Eiichi , Karsenty Gerard , Ducy Patricia
Published: March 2008

The osteoblast-specific secreted molecule osteocalcin behaves as a hormone regulating glucose metabolism and fat mass in two mutant mouse strains. Here, we ask two questions: is the action of osteocalcin on β cells and adipocytes elicited by the same concentrations of the molecule, and more importantly, does osteocalcin regulate energy metabolism in WT mice? Cell-based assays using isolated pancreatic islets, a β cell line, and primary adipocytes showed that picomolar amounts of osteocalcin are sufficient to regulate the expression of the insulin genes and β cell proliferation markers, whereas nanomolar amounts affect adiponectin and Pgc1α expression in white and brown adipocytes, respectively.
In vivo
the same difference exists in osteocalcin's ability to regulate glucose metabolism on the one hand and affect insulin sensitivity and fat mass on the other hand. Furthermore, we show that long-term treatment of WT mice with osteocalcin can significantly weaken the deleterious effect on body mass and glucose metabolism of gold thioglucose-induced hyperphagia and high-fat diet. These results establish in WT mice the importance of this novel molecular player in the regulation of glucose metabolism and fat mass and suggest that osteocalcin may be of value in the treatment of metabolic diseases.
Directly dated starch residues document early formative maize (
Zea mays
L.) in tropical Ecuador
Authors: Zarrillo Sonia , Pearsall Deborah M. , Raymond J. Scott , Tisdale Mary Ann , Quon Dugane J.
Published: March 2008

The study of maize (
Zea mays
L.) domestication has advanced from questions of its origins to the study—and debate—of its dietary role and the timing of its dispersal from Mexico. Because the investigation of maize's spread is hampered by poor preservation of macrobotanical remains in the Neotropics, research has focused on microbotanical remains whose contexts are often dated by association, leading some to question the dates assigned. Furthermore, some scholars have argued that maize was not introduced to southwestern Ecuador until ≈4150–3850 calendar years before the present (cal B.P.), that it was used first and foremost as a fermented beverage in ceremonial contexts, and that it was not important in everyday subsistence, challenging previous studies based on maize starch and phytoliths. To further investigate these questions, we analyzed every-day cooking vessels, food-processing implements, and sediments for starch and phytoliths from an archaeological site in southwestern Ecuador constituting a small Early Formative village. Employing a new technique to recover starch granules from charred cooking-pot residues we show that maize was present, cultivated, and consumed here in domestic contexts by at least 5300–4950 cal B.P. Directly dating the residues by accelerator mass spectrometry (AMS) radiocarbon measurement, our results represent the earliest direct dates for maize in Early Formative Ecuadorian sites and provide further support that, once domesticated ≈9000 calendar years ago, maize spread rapidly from southwestern Mexico to northwestern South America.
IL-15 as a mediator of CD4
+
help for CD8
+
T cell longevity and avoidance of TRAIL-mediated apoptosis
Authors: Oh SangKon , Perera Liyanage P. , Terabe Masaki , Ni Ling , Waldmann Thomas A. , Berzofsky Jay A.
Published: March 2008

CD4
+
helper T cells contribute to the induction and maintenance of antigen-specific CD8
+
T cells. Their absence results in short-lived antigen-specific CD8
+
T cells and defective secondary CD8
+
T cell responses because of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis. Here, we show that IL-15 codelivered with vaccines can overcome CD4
+
T cell deficiency for promoting longevity of antigen-specific CD8
+
T cells and avoidance of TRAIL-mediated apoptosis. In both priming and secondary responses, IL-15 down-regulates proapoptotic Bax, an intermediate in TRAIL-mediated apoptosis, and increases anti-apoptotic Bcl-X
L
in CD8
+
T cells. Thus, IL-15 is sufficient to mimic CD4
+
T cell help. Antigen-specific CD4
+
T cells induce dendritic cells (DCs) to produce IL-15. IL-15 is also necessary for optimal help, because helper cells do not deliver effective help through IL-15
−/−
DCs. Therefore, IL-15 codelivered with vaccines can overcome CD4
+
helper T cell deficiency for induction of functionally efficient CD8
+
T cells and maintenance of CD8
+
cytotoxic T lymphocytes (CTLs), and IL-15 is probably one of the natural mediators of help. These findings suggest new vaccine strategies against infections and cancers, especially in individuals with CD4-deficiency.
Accessory renal artery stenosis and hypertension: are these correlated? evaluation using multidetector-row computed tomographic angiography
Authors: Saba L. , Sanfilippo R. , Montisci R. , Conti M. , Mallarini G.
Published: March 2008

Background: Renal artery stenosis may produce hypertension, and this condition is referred to as renovascular hypertension (RVH).

Purpose: To evaluate, by using multidetector-row spiral computed tomographic angiography (MDCTA), whether a relationship between accessory renal artery stenosis and hypertension may be hypothesized.

Material and Methods: 214 patients (142 males, 72 females; mean age 66 years) who had previously undergone an MDCTA to study the abdominal vasculature were retrospectively studied. Patients with renal artery stenosis (RAS) were excluded from this analysis. The patients were studied by means of a four-detector-row CT, and scans were obtained after intravenous bolus administration of 110–140 ml of a nonionic contrast material with a 3–6 ml/s flow rate. As a second step, by means of statistical analysis, hypertension data were compared with findings of accessory artery stenosis. Two radiologists first independently reviewed the MDCTA images and then, in case of disagreement, in consensus. Interobserver agreement was calculated for all measurements.

Results: The overall number of detected accessory renal arteries was 74 in 56 of the 214 patients. Accessory renal artery stenosis was detected in 21 of the 56 patients. There was a difference in the prevalence of hypertension between patients with ( n = 21) and without ( n = 35) accessory renal artery stenosis ( P = 0.0187). Interobserver agreement was good (kappa value 0.733).

Conclusion: Any statistical association between the presence of accessory renal artery stenosis and hypertension could not be disclosed. However, accessory renal artery stenosis, detected by MDCTA, is an important pathological sign that the radiologist has to assess in the light of its possible association with hypertension.
Anaplastic thyroid carcinoma: computed tomographic differentiation from other thyroid masses
Authors: Lee Jun Won , Yoon Dae Young , Choi Chul Soon , Chang Suk Ki , Yun Eun Joo , Seo Young Lan , Rho Young-Soo , Cho Sung Jin , Kim Keon Ha
Published: March 2008

Background: Anaplastic thyroid carcinoma is rare but is one of the most aggressive malignancies. Therefore, accurate diagnosis is important in order to provide appropriate therapy.

Purpose: To establish useful computed tomographic (CT) criteria for differentiating anaplastic carcinoma from other thyroid masses.

Material and Methods: The CT scans of nine patients with anaplastic carcinomas were retrospectively reviewed and compared with those of 32 patients with papillary carcinomas ( n = 12) or benign lesions ( n = 20) exceeding a maximum diameter of 2.0 cm. Image analysis was performed according to the following CT parameters: size, margin (well defined or ill defined), composition (cystic, mixed, or solid), mean attenuation value, ratio of attenuation of the mass to that of the adjacent muscle (M/m attenuation ratio), necrosis (present or absent), and calcification (stippled, nodular, or absent) of the thyroid mass; and tumor-spreading patterns including the presence of surrounding normal thyroid tissue in the involved lobe, involvement of the contralateral thyroid lobe, extension into the adjacent structures, and cervical lymphadenopathy.

Results: Anaplastic carcinomas appeared as large (average 4.6 cm), solid (100%), and ill-defined (88.9%) masses accompanied by necrosis (100%), nodular calcification (44.4%), direct invasion into the adjacent organs (55.6%), and cervical lymph node involvement (77.8%). Tumor necrosis was the most valuable parameter in differentiating anaplastic carcinomas from other thyroid masses. Patient age (>70 years) and low attenuation value on postcontrast scan (attenuation value <100 HU, or M/m attenuation ratio <1.3) are also helpful predictors for anaplastic carcinoma.

Conclusion: If a patient is older than 70 years of age and has a large necrotic thyroid mass of low attenuation, anaplastic carcinoma should be included in the differential diagnosis.
Detection and characterization of focal liver lesions with contrast-enhanced ultrasonography in patients with hepatitis c-induced liver cirrhosis
Authors: Rahbin N. , Siösteen A.-K. , Elvin A. , Blomqvist L. , Hagen K. , Hultcrantz R. , Aleman S.
Published: March 2008

Background: Hepatitis C virus (HCV)-associated liver cirrhosis provides a major preneoplastic condition for hepatocellular carcinoma (HCC). Ultrasonography (US) is usually used for screening of HCC, but needs improvement.

Purpose: To assess whether use of a second-generation ultrasound contrast agent can improve characterization of focal liver lesions and detection of HCC in HCV-infected patients with liver cirrhosis.

Material and Methods: In total, 96 US studies in 49 HCV-infected patients with liver cirrhosis were performed. The patients were first examined with a baseline US. After this, a diagnostic decision was made and recorded. The patients were then re-examined with contrast-enhanced ultrasound (CEUS), and the diagnostic triage was repeated. The patients were followed up for at least 1 year.

Results: On baseline US, indeterminate focal lesions were found in 27 examinations. After CEUS, a confident diagnosis of HCC was made in eight of these examinations. In an additional eight US examinations, diagnosis of regenerative/dysplastic noduli was established. In one patient with no detectable focal lesion at baseline examination, an indeterminate malignant lesion was detected with CEUS. This lesion was further investigated with computed tomography and diagnosed as HCC.

Conclusion: Our study indicates that the use of CEUS significantly improves diagnostic confidence. CEUS improves the detection of HCC in patients with HCV-induced liver cirrhosis. Also, CEUS makes it possible to rule out malignancy in many cases where baseline US shows indeterminate focal lesions. In low-endemic countries, the use of CEUS in screening for HCC may be considered.
Simple microwire and microcatheter mechanical thrombolysis with adjuvant intraarterial urokinase for treatment of hyperacute ischemic stroke patients
Authors: Kim Dong Joon , Kim Dong Ik , Byun Joon Soo , Jung Jin Young , Suh Sang Hyun , Kim Eung Yeop , Lee Kyung-Yul , Heo Ji Hoe
Published: March 2008

Background: Mechanical thrombolysis may effectively enhance the efficacy of thrombolysis for hyperacute ischemic stroke patients.

Purpose: To assess the feasibility and results of simple mechanical-based thrombolysis using microwire and microcatheter with adjuvant low-dose intraarterial (i.a.) urokinase (UK) for the treatment of hyperacute ischemic stroke.

Material and Methods: Nineteen consecutive patients with hyperacute proximal middle cerebral artery (MCA) occlusions treated by a standardized protocol using microwire and microcatheter for mechanical thrombus disruption with adjuvant i.a. UK were reviewed. Simple to-and-fro passages through the clot with the microwire and microcatheter followed by disruptions by a J- or pigtail-shaped wire tip with alternating small-dose injections of UK distal, within, and proximal to the clot were performed. The recanalization rates, post-thrombolysis hemorrhage, and clinical outcome (baseline and discharge National Institute of Health Stroke Scale [NIHSS], mortality, 3-month modified Rankin scale [mRS]) were evaluated.

Results: Recanalization was achieved in 18 of 19 patients (94.7%). The mean UK dose was 375,789 IU (range 130,000–580,000 IU). Two patients (10.5%) developed symptomatic hemorrhage. One of the hemorrhages included a patient who developed subarachnoid hemorrhage. Mortality rate was 15.8% ( n = 3). The median baseline NIHSS scores showed improvement from 17 to 10 at presentation and discharge, respectively. At three months, good outcome was noted in 11 of 19 patients (57.9%, mRS 0–2).

Conclusion: Simple mechanical-based thrombolysis using microwire and microcatheter with adjuvant low-dose i.a. UK is safe and effective in achieving recanalization with good long-term outcome.
Magnetic resonance imaging of the cranial nerves in the posterior fossa: a comparative study of t2-weighted spin-echo sequences at 1.5 and 3.0 tesla
Authors: Fischbach F. , Müller M. , Bruhn H.
Published: March 2008

Background: High-field magnetic resonance imaging (MRI) at 3.0 Tesla (T) is rapidly gaining clinical acceptance. Whether doubling of the field strength of 1.5T and the subsequent increase in signal-to-noise ratio (SNR) leads to a significant improvement of image quality is not automatically given.

Purpose: To evaluate the depiction of fine anatomic detail in the posterior fossa, focusing on brain nerves, on T2-weighted imaging, and to define the potential advantage of imaging at 3.0T versus 1.5T.

Material and Methods: In total, 10 brainstem nerve pairs of 12 volunteers were identified on T2-weighted MR images of 2- and 5-mm section thickness acquired at 1.5T and 3.0T. The MR images were compared for each subject at both field strengths by three independent readers who rated image quality according to depiction of anatomic detail and contrast by using a rating scale.

Results: In general, MR images at 3.0T were considered more conspicuous and less noisy than images at 1.5T. The SNR value measured was almost doubled. With respect to structural identification and contrast according to the rating scale, observer scores were significantly improved both for standard imaging with 5-mm sections and high-resolution imaging with 2-mm sections at 3.0T. Direct comparison revealed a significant increase for evaluated image quality criteria and the number of nerves detected.

Conclusion: The comparison revealed a clear advantage in favor of T2-weighted MRI at 3.0T vs. 1.5T in depicting the roots and course of brain nerves in the posterior fossa.
Book Review
Authors: Tikkakoski Tapani
Published: March 2008

Head and Neck: Direct Diagnosis in Radiology. Edited by U. Moedder, M. Cohnen, K. Andersen, V. Engelbrecht and B. Fritz. Georg Thieme Verlag, Stuttgart, 2008. ISBN 978-1-58890-564-2 (the Americas); ISBN: 978-3-13-144081-5 (rest of the world). 262 pages.
Iodinated contrast media: effect of osmolarity and injection temperature on erythrocyte morphology in vitro
Authors: Kerl J. M. , Nguyen S. A. , Lazarchick J. , Powell J. W. , Oswald M. W. , Alvi F. , Costello P. , Vogl T. J. , Schoepf U. J.
Published: March 2008

Background: Some side effects of intravenously injected iodinated contrast media are thought to be linked to the biological properties of the various agents and their effect on blood components.

Purpose: To assess the effect of osmolarity and injection temperature of iodinated contrast media on erythrocyte (RBC) morphology in vitro.

Material and Methods: Blood from 20 volunteers was incubated with three different contrast media (320 mg I/ml iso-osmolar iodixanol, 300 mg I/ml low-osmolar iopromide, 300 mg I/ml low-osmolar iopamidol) injected at 37°C, 43°C, and 48°C, and in two different volumes corresponding to the estimated concentration at the site of venous injection and after systemic distribution. After 10 min incubation, aliquots were removed for complete blood count analysis and blood smears. Two hematologists blindedly and independently reviewed all smears, and determined the grade of morphological RBC changes compared to a blank sample.

Results: There was excellent (κ = 0.98) inter-reader correlation for grading RBC changes. At systemic concentration at 37°C, the grade of RBC changes was significantly ( P<0.05) less in blood samples exposed to iso-osmolar iodixanol (mean 0.21) as compared to low-osmolar iopromide (mean 0.26) and low-osmolar iopamidol (mean 0.58). These differences became more significant at higher volumes, corresponding to concentrations at the site of injection and higher injection temperatures.

Conclusion: In vitro, RBC morphology is less affected by iso-osmolar as compared to low-osmolar contrast media. These differences become more significant at higher injection temperatures that are proposed to improve flow dynamics for high-speed injection.
Nutrition, the brain and prolonged exercise
Authors: Watson Phil
Published: March 2008

Possible peripheral mechanisms of fatigue have been widely documented, including the depletion of muscle glycogen and the loss of body fluids. The notion that the brain may be intimately involved in the fatigue process is not a new one, but recently possible neurobiological mechanisms involved in this response have been investigated. Changes in central neurotransmission occur during exercise that may result in feelings of tiredness, lethargy, and a loss of motivation to continue exercise, contributing to the development of fatigue. There is evidence that manipulation of the neurotransmitters serotonin, dopamine, and noradrenaline, through the administration of pharmacological agents, may delay the onset of fatigue during prolonged exercise, particularly when performing in a warm environment. Supplementation with branched‐chain amino acids and tyrosine can influence perceived exertion and some measures of mental performance, but the results of several apparently well‐controlled laboratory studies have not demonstrated a positive effect on exercise capacity under temperate conditions. The ergogenic effects of carbohydrate and caffeine are well documented, but often little attention is paid to the central effects of these nutrients. Carbohydrate ingestion has been demonstrated to alter brain activity and cerebral metabolism, factors that may be important in the development of fatigue and the maintenance of skill performance. There is strong evidence for a positive effect of caffeine on exercise performance, with recent data highlighting the role of central adenosine as a mediator of this response.
Alum adjuvant boosts adaptive immunity by inducing uric acid and activating inflammatory dendritic cells
Authors: Kool Mirjam , Soullié Thomas , van Nimwegen Menno , Willart Monique A.M. , Muskens Femke , Jung Steffen , Hoogsteden Henk C. , Hammad Hamida , Lambrecht Bart N.
Published: March 2008

Alum (aluminum hydroxide) is the most widely used adjuvant in human vaccines, but the mechanism of its adjuvanticity remains unknown. In vitro studies showed no stimulatory effects on dendritic cells (DCs). In the absence of adjuvant, Ag was taken up by lymph node (LN)–resident DCs that acquired soluble Ag via afferent lymphatics, whereas after injection of alum, Ag was taken up, processed, and presented by inflammatory monocytes that migrated from the peritoneum, thus becoming inflammatory DCs that induced a persistent Th2 response. The enhancing effects of alum on both cellular and humoral immunity were completely abolished when CD11c+ monocytes and DCs were conditionally depleted during immunization. Mechanistically, DC-driven responses were abolished in MyD88-deficient mice and after uricase treatment, implying the induction of uric acid. These findings suggest that alum adjuvant is immunogenic by exploiting “nature's adjuvant,” the inflammatory DC through induction of the endogenous danger signal uric acid.
INHIBITION OF CONVERSION OF THYROXINE TO TRIIODOTHYRONINE IN PATIENTS WITH SEVERE CHRONIC ILLNESS
Authors: CARTER J. N. , EASTMAN C. J. , CORCORAN J. M. , LAZARUS L.
Published: March 2008

Many clinically euthyroid patients with severe, chronic, non‐thyroidal illnesses (i.e. sick euthyroid patients) have very low circulating concentrations of total and absolute free triiodothyronine (T3), low‐normal concentrations of total thyroxine (T4), elevated concentrations of absolute free T4, and circulating concentrations of thyrotrophin (TSH) that are either normal or subnormal. This study was undertaken to elucidate the mechanism of the low circulating T3 concentrations. The disappearance rate of 125I‐T3 from the circulation of five representative sick euthyroid patients, was studied and found to be slower, but not significantly so, compared with three control subjects, thus excluding an increased destruction rate as the cause of the low T3 levels. A selective decrease of T3 secretion from the thyroid gland of these patients was also excluded by the results of TSH stimulation tests. Inhibition of extra‐thyroidal conversion of T4 to T3 was suggested by studies of the thyroid function in a hypothyroid woman with a Grade IV lymphoma on T4 replacement therapy. When the lymphoma was in remission, her circulating T3 concentration was 2–55 nmol/1 but when it relapsed it fell to 0–55 nmol/1. The T4 concentrations were 124–7 nmol/1 and 126 nmol/1 respectively. Decreased monodeiodination of T4 to T3 in sick euthyroid patients was confirmed by paper chromatography of extracted serum obtained 48 h after an i.v. injection of 125I‐T4 into two severely ill patients from the intensive therapy unit and a control subject. Peaks of radioactivity corresponding to 125I‐T4 and 125I‐T3 were detected in the control subject, but only a single peak corresponding to 125I‐T4 was detected in the ill patients.
TRANSPLACENTAL GRADIENTS OF SEX‐HORMONE‐BINDING GLOBULIN IN HUMAN AND SIMIAN PREGNANCY
Authors: ANDERSON D. C. , LASLEY B. L. , FISHER R. A. , SHEPHERD J. H. , NEWMAN L. , HENDRICKX A. G.
Published: March 2008

An attempt has been made to clarify the degree and control of production of the concentration gradient of sex‐hormone‐binding globulin (SHBG) between human mother and fetus. SHBG was measured by an improved ammonium sulphate precipitation method using 5α‐dihydrotestosterone as ligand. Maternal and fetal (cord blood) plasma SHBG was measured at delivery in twenty‐three normal, four twin and one anencephalic pregnancies and in non‐pregnant subjects. Comparison was also made with two macaque species, the rhesus monkey (M. mulatto) and the bonnet monkey (M. radiata), sampled shortly after delivery.

In the human, a highly consistent gradient (mean 21‐fold) was found between mother and fetus, which was independent of fetal sex and weight. Fetal but not maternal SHBG was significantly higher in the twin pregnancies. Maternal SHBG was 5‐fold higher than in forty non‐pregnant women, and fell with a half‐life of 7.1 days immediately post‐partum.

In the two monkey species, SHBG with similar binding‐characteristics exists but levels were 2.5‐fold higher in the non‐pregnant adult females than in women. In pregnancy, maternal SHBG levels were unchanged in the bonnet (nine observations) and fell markedly in the rhesus monkey (twenty‐three observations); levels in the infants were comparably low in all three species, though more variable in the monkeys. In seven bonnet monkey mother‐infant pairs sampled again 2 or 8 weeks later, SHBG had risen markedly (mean 6.1‐fold) in the infants as has been shown previously in the human. The species differences in the non‐pregnant females and the mothers may in part be related to species differences in oestrogen production. The macaque monkey appears suitable for studying further the mechanism of the neonatal SHBG rise, in which oestrogens cannot be implicated but thyroid hormones may be involved.
Information systems and uncertainty: a conspiracy of misplaced confidence
Authors: Straub B. , Angell IO
Published: March 2008

Abstract. Information technology is becoming an increasingly important factor in contemporary management. Information systems are being set up in business explicitly to accommodate the new opportunities of this technology, and these are having a lasting effect on managerial practice. The full implications of this technology‐driven development have not been appreciated by organizations, which in absorbing technological systems, are tolerating a great drain on their resources.

The efficacy of computers is predicated on the acceptance of some very specific perspectives. A growing discontent and disappointment with their limited achievements is our reason for advocating a different point of view. We will discuss how a shift in perspective, particularly in respect to the perception of uncertainty, will affect thinking and practice in the field of management support systems. We will render our view of the application of computerized decision support systems (DSS), and especially, we will focus on the beliefs and assumptions that have shaped this technology thus far. To this end we will discuss the concept of uncertainty, by juxtaposing current thinking and practice with our understanding of the context of its application. Finally, we will place our understanding of uncertainty in a managerial context and explain the implications this would have for strategists.
The design of large knowledge‐based systems: the example of Digital Equipment's XSEL project
Authors: Mumford E.
Published: March 2008

Abstract. This paper discusses the management problems associated with building and implementing large systems. The example described is XSEL, a configuring expert system designed by the Digital Equipment Corporation for worldwide application.

Digital, like many other larger computer manufacturers, had experienced problems in achieving a high level of configuring accuracy when assembling its computer. These problems showed up in the manufacturing plants but originated in the sales offices. They caused difficulties with customers and increased manufacturing and selling costs. The company decided that an expert system could solve the problem.

The processes associated with the design of this successful system created as many human as technical challenges. The paper describes these, discusses how and why they originated, and evaluates Digital's strategies for solving them. It makes some general recommendations for the successful management of major change.
Towards client‐led development of information systems
Authors: Stowell F. A.
Published: March 2008

Abstract. With the incorporation of Information Technology into most areas of modern life, the methods used by the Computer System Analyst (CSA) needs to be reconsidered. To suppose Systems Analysis to be concerned solely with computing is to minimize the task as an information system is greater than a computer system. As such, the information system designer needs to be able to ‘appreciate’ the wider implications of a clients information needs. An argument is put forward that Information System Design should be undertaken by the client with the CSA acting as facilitator. This paper attempts to provide a re‐appraisal of the CSA and arising from this re‐appraisal, suggest that ideas originating from organizational analysis could be usefully embodied in the design process for Information Systems.
A domain selection and evaluation framework for introducing knowledge‐based systems in smaller businesses
Authors: Martinsons Maris G.
Published: March 2008

Abstract. As the use of knowledge‐based systems becomes increasingly viable, small business managers face decisions related to the introduction and integration of this information technology into their organizations. This article provides a framework to evaluate domains for knowledge‐based applications development.
Negotiation support systems: roots, progress and needs
Authors: Holsapple C W , Lai H , Whinston A B
Published: March 2008

Abstract. This paper identifies game theories and social behavior science as important roots for negotiation support systems (NSS) research. As these are not typically cited in the NSS literature, summary reviews of them are provided with indications of their relevance to NSS study. On the other hand, neither offers a sufficiently general‐purpose formal model of negotiation that could serve as a backbone for NSS research. A survey of that research is provided, indicating that prugress to date has been somewhat eclectic and devoid of such a model. Our central contention is that a theoretical foundation for NSS study is much needed. Desirable characteristics of a suitable negotiation model are identified as guidance for future research that will aim to devise (and subsequently apply and test) such a model.
CD‐ROM: an effective use of technology?
Authors: Armstrong CJ
Published: March 2008

Abstract. The correct use of information systems implies, in part, the effective delivery and use of information. In situations where, as has frequently been the case in recent years, CD‐ROMs form a part of an information system, there is very little that users can do to regulate or control the quality of the information being supplied. Poor information cannot be effectively used. This paper discusses the effective use of the medium and questions whether all publishers are paying sufficient attention to quality.
Knowledge elicitation as an inquiring system: towards a ‘subjective’ knowledge elicitation methodology
Authors: West D.
Published: March 2008

Abstract. Many researchers in the field of knowledge elicitation (KE) have recognized the importance of the role of ‘expertise’ for the development of expert systems. This recognition has led to attempts to classify knowledge ‘types’ and define ‘genericxyr task structures so as to reduce the complexity of the KE process (Gammack & Young, 1985; Breuker & Wielinga, 1987; Welbank, 1987). The success of such an approach has been debatable as expertise has proved difficult to classify (Burton et al., 1987), with different researchers adopting different catagorizations. The research reported in this paper attempts to develop a broad view of ‘expertise’ by drawing upon Vicker's notion of ‘appreciation’ (1965). This, it is argued, can help to provide a useful description of the way in which expertise is gained and practised. The model suggested also takes into account the more ‘subjective’ aspects of human expertise (i.e. it allows for such components as intuition, personal experience and belief, bias and even prejudice). The view of expertise put forward is developed as a theoretical basis for a practical subjective approach to KE. As a result of this model, the author suggests that instead of concentrating upon the process of extraction, KE may be more usefully thought of as a process of inquiry through which, as described by Churchman (1971), knowledge, or expertise is produced. Some ideas that deal with ‘inquiring systems’ are examined here as an appropriate framework for the KE process.