bluuebunny/crossref_metadata_2025 huggingface dataset:
Populist Mobilization: A New Theoretical Approach to Populism
Authors: Jansen Robert S.
Published: June 2011

Sociology has long shied away from the problem of populism. This may be due to suspicion about the concept or uncertainty about how to fit populist cases into broader comparative matrices. Such caution is warranted: the existing interdisciplinary literature has been plagued by conceptual confusion and disagreement. But given the recent resurgence of populist politics in Latin America and elsewhere, sociology can no longer afford to sidestep such analytical challenges. This article moves toward a political sociology of populism by identifying past theoretical deficiencies and proposing a new, practice-based approach that is not beholden to pejorative common sense understandings. This approach conceptualizes populism as a mode of political practice—as populist mobilization. Its utility is demonstrated through an application to mid-twentieth-century Latin American politics. The article concludes by sketching an agenda for future research on populist mobilization in Latin America and beyond.
An Actor-Network Theory of Cosmopolitanism
Authors: Saito Hiro
Published: June 2011

A major problem with the emerging sociological literature on cosmopolitanism is that it has not adequately theorized mechanisms that mediate the presumed causal relationship between globalization and the development of cosmopolitan orientations. To solve this problem, I draw on Bruno Latour's actor-network theory (ANT) to theorize the development of three key elements of cosmopolitanism: cultural omnivorousness, ethnic tolerance, and cosmopolitics. ANT illuminates how humans and nonhumans of multiple nationalities develop attachments with one another to create network structures that sustain cosmopolitanism. ANT also helps the sociology of cosmopolitanism become more reflexive and critical of its implicit normative claims.
The Solution to the Consequence Problem According to Anti‐Individualism
Authors: Barel Frank
Published: June 2011

Abstract:For quite some time now there has been an ongoing debate whether authoritative self‐knowledge is compatible with anti‐individualism.1One influential line of argument against compatibilism is due toPaul Boghossian (1998). I argue that Boghossian misconstrues what the anti‐individualist really is committed to. This defence of compatibilism is elaborated by showing how the Twin Earth thought experiment is meant to speak in favour of anti‐individualism. Partly this will show that Boghossian is wrong in his denial that empirical background knowledge is imported into the Twin Earth experiment. The main points argued are that Boghossian fails to realize, both, (1) that anti‐individualism does not involve concept‐individuation in terms of reference, and (2) that anti‐individualism assumes a core of representational success. In effect, these two points constitute an entirely new way to defend compatibilism, a way that seems to have gone unnoticed in the literature.
Transfusion requirements in obstetric patients with placenta accreta
Authors: Stotler Brie , Padmanabhan Anand , Devine Patricia , Wright Jason , Spitalnik Steven L. , Schwartz Joseph
Published: June 2011

BACKGROUND: Providing transfusion support for patients with placenta accreta is a challenging task. There is no consensus on predelivery transfusion planning for these patients and the prevalence of massive transfusion is unknown. With little published experience, it is difficult to predict blood component usage accurately. Therefore, this retrospective study spanning 14 years quantified blood usage and clinical outcome in a group of patients with placenta accreta.

STUDY DESIGN AND METHODS: A retrospective medical record review identified 66 patients with placenta accreta who presented for delivery. Data were extracted from the patients' medical records related to patient demographics, pathology diagnosis, blood component usage, operative course, and clinical outcome. Selected variables were analyzed for statistical association with total blood component usage.

RESULTS: The range of blood component usage was 0 to 46 red blood cell (RBC) units, 0 to 48 random‐donor platelet unit equivalents, 0 to 64 plasma units, and 0 to 30 cryoprecipitate units. The incidence of transfusion was 95% (mean RBC use, 10 ± 9 units; median, 6.5 units), with 39% of patients requiring 10 or more RBC units and 11% requiring 20 or more RBC units. Blood component use did not differ significantly between the pathology‐defined placenta accreta subtypes. Potential clinical laboratory variables that would predict increased blood component use were not identified.

CONCLUSION: The delivery of patients with placenta accreta is a high‐risk procedure that requires multidisciplinary planning and adequate resources to optimize outcome. Transfusion services should have a protocol for managing these cases that addresses preoperative blood component preparation and intraoperative management, should massive hemorrhage occur.
Anti‐D investigations in individuals expressing weak D Type 1 or weak D Type 2: allo‐ or autoantibodies?
Authors: Pham Bach‐Nga , Roussel Michèle , Peyrard Thierry , Beolet Marylise , Jan‐Lasserre Véronique , Gien Dominique , Ripaux Maryline , Bourgouin Sébastien , Kappler‐Gratias Sandrine , Rouger Philippe , Pennec Pierre‐Yves Le
Published: June 2011

BACKGROUND: Whether anti‐D produced by individuals with a weak D phenotype are allo‐ or autoantibodies remains a matter of debate even though blood transfusion practice is impacted. The aim of our study was to determine the serologic features of anti‐D in individuals expressing the most frequent weak D type in Caucasians that are weak D Type 1 or weak D Type 2, to assess whether anti‐D were allo‐ or autoantibodies.

STUDY DESIGN AND METHODS: Serologic D typing and molecular analysis enabled the including of 121 weak D Type 1 individuals and 99 weak D Type 2 individuals in our study. Serologic features of anti‐D included autologous controls, direct antiglobulin test, elution, and titration of anti‐D before and after adsorption of serum on autologous red blood cells (RBCs).

RESULTS: Serologic D typing showed a variable reactivity of RBCs expressing weak D Type 1 or weak D Type 2 (4+ to 0). Anti‐D was identified in six weak D Type 1 and six weak D Type 2 individuals, respectively. The serologic data were in favor of autoantibodies.

CONCLUSION: A complete anti‐D investigation in individuals with a D variant (weak D or partial D identified by molecular analysis) should be systematically performed before any valid conclusion on the nature of the antibody. Transfusing weak D Type 1 or weak D Type 2 patients with D+ RBC units should be recommended. Weak D Type 1 or weak D Type 2 pregnant women do not need anti‐D immunoprophylaxis.
Differentiation between pancreatic carcinoma and mass‐forming chronic pancreatitis: Usefulness of high b value diffusion‐weighted imaging
Authors: HUANG Wen Cai , SHENG Jing , CHEN Shi Yue , LU Jian Ping
Published: June 2011

OBJECTIVE:  To investigate the value of high b value diffusion‐weighted (DW) imaging in differentiating between pancreatic carcinoma and mass‐forming chronic pancreatitis (MFCP).

METHODS:  Fifty‐one consecutive patients with pathology‐proven pancreatic carcinoma (n = 37) or MFCP (n = 14) were evaluated with DW imaging (b value, 0 and 1000 s/mm2) at a 3‐T MR system. Overall 20 healthy volunteers were evaluated as the control group. The apparent diffusion coefficient (ADC) values of normal pancreas, pancreatic carcinoma, MFCP, and mass‐associated obstructive pancreatitis were measured.

RESULTS:  On high b value (1000 s/mm2) DW images, both pancreatic carcinoma and MFCP were hyperintense focal lesions; mass‐associated obstructive pancreatitis occurred in 17 of 37 (45.9%) pancreatic carcinoma and 8 of 14 (57.1%) MFCP. The ADC (×10−3 mm2/s) of the pancreatic carcinomas (1.06 ± 0.15) was significantly lower than that of normal pancreas (1.47 ± 0.18; P < 0.01), MFCP (1.35 ± 0.14; P < 0.01) and mass‐associated chronic pancreatitis (1.44 ± 0.17; P < 0.01). The ADC of MFCP was also lower than that in the normal pancreas (P = 0.025), whereas the ADC of mass‐associated obstructive pancreatitis was not different from those of the MFCP (P = 0.113) and normal pancreas (P = 0.544). When 1.195 was used as the optimal cut‐off value, ADC quantification obtained a sensitivity of 85.7% and a specificity of 86.5% for differentiating pancreatic carcinomas from MFCP.

CONCLUSION:  High b value DW imaging in combination with ADC quantification at a 3‐T MR system is useful in differentiating between pancreatic carcinoma and MFCP.
No effect of co-administered antiepileptic drugs on in-vivo protein binding parameters of valproic acid in patients with epilepsy
Authors: Suzuki Yosuke , Itoh Hiroki , Abe Tomohide , Nishimura Fumihiro , Sato Yuhki , Takeyama Masaharu
Published: June 2011

Objectives

The aim of this study was to establish the population protein binding parameters of valproic acid (VPA) in patients with epilepsy receiving VPA monotherapy and those receiving VPA combined with other antiepileptic drugs.

Methods

One hundred and thirty nine data sets from 63 Japanese patients with epilepsy were analysed. These patients were separated into two groups: VPA monotherapy and VPA combined with other binding-sensitive antiepileptic drugs, including phenytoin, clonazepam, clobazam, carbamazepine and phenobarbital (VPA polytherapy). The population protein-binding parameters of VPA were obtained by non-linear least-squares method in each group.

Key findings

The mean (95% confidence interval) dissociation constants were 38.9 µm (33.2–44.6 µm) and 36.9 µm (26.7–47.1 µm), and the numbers of binding sites were 1.36 (1.27–1.44) and 1.33 (1.19–1.47) in the monotherapy and polytherapy groups, respectively. No significant differences in the binding parameters of VPA to serum albumin were observed between the two groups.

Conclusions

The steady-state serum albumin binding of VPA in Japanese patients with epilepsy is not affected by co-administration of other antiepileptic drugs. These findings suggest that serum VPA concentration is stable at the steady state with regard to interaction by protein binding, even when other antiepileptic drugs with moderate-to-high binding properties are co-administered.
Hepato-/reno-protective activity of Chinese prescription Kangen-karyu through inhibition of AGE formation and fibrosis-related protein expression in type 2 diabetes
Authors: Okamoto Takuya , Park Chan Hum , Noh Jeong Sook , Toriizuka Kazuo , Sei Yasuo , Park Jong Cheol , Yokozawa Takako
Published: June 2011

Objectives

This study was conducted to examine whether Kangen-karyu, a Chinese prescription, has an ameliorative effect on diabetes-induced alterations such as advanced glycation endproduct (AGE) formation or the fibrotic response in liver and kidney of type 2 diabetic db/db mice.

Methods

Kangen-karyu (100 or 200 mg/kg body weight/day, p.o.) was administered every day for 18 weeks to db/db mice, and its effect was compared with vehicle-treated db/db and m/m mice.

Key findings

The administration of Kangen-karyu decreased the elevated serum glucose concentration in db/db mice. The increased serum creatinine and urea nitrogen levels, which reflect renal dysfunction in db/db mice, were significantly lowered by Kangen-karyu administration. The db/db mice exhibited the up-regulation of AGEs and its receptor expression in liver and kidney; however, Kangen-karyu treatment significantly reduced expression except for the receptor. Moreover, the augmented expressions of fibrosis-related proteins, transforming growth factor (TGF)-β1, fibronectin and collagen IV were down-regulated by Kangen-karyu administration.

Conclusions

These results provide important evidence that Kangen-karyu exhibits a pleiotropic effect on AGE formation and fibrosis-related parameters, representing hepatoprotective and renoprotective effects against the development of diabetic complications in type 2 diabetic db/db mice.
Multicentric Evaluation of New Commercial Enzyme Immunoassays for the Detection of Immunoglobulin M and Total Antibodies against Hepatitis A Virus
Authors: Arcangeletti M. C. , Dussaix E. , Ferraglia F. , Roque-Afonso A. M. , Graube A. , Chezzi C.
Published: June 2011

A multicentric clinical study was conducted on representative sera from 1,738 European and U.S. subjects for the evaluation of new anti-hepatitis A virus enzyme immunoassays from Bio-Rad Laboratories. Comparison with reference DiaSorin S.p.A. tests confirmed the good performance of Bio-Rad assays (99.85% and 99.47% overall agreement in detecting total antibodies and IgM, respectively).
Suitability of Xpert MTB/RIF and Genotype MTBDR
plus
for Patient Selection for a Tuberculosis Clinical Trial
Authors: Friedrich Sven O. , Venter Amour , Kayigire Xavier A. , Dawson Rodney , Donald Peter R. , Diacon Andreas H.
Published: June 2011

Participation criteria for clinical trials in pulmonary tuberculosis commonly include confirmation of sputum positive for mycobacteria and an indication of drug susceptibility before treatment is initiated. We investigated the suitability of two novel sputum-based nucleic acid amplification methods for patient selection in a recent early bactericidal activity study. Spontaneously expectorated sputum samples of 140 consecutive pulmonary tuberculosis patients were examined with direct fluorescence microscopy, Genotype MTBDR
plus
assay (MTBDR), Xpert MTB/RIF assay (Xpert), and liquid mycobacterial culture. The methods detected mycobacteria or mycobacterial DNA in 96.8%, 90.5%, 92.9%, and 92.1% of samples, respectively. MTBDR, Xpert, and liquid culture were 100% concordant for detection of resistance to rifampin. Sensitivity and specificity of MTBDR for detection of isoniazid resistance were 83.3% and 100%, respectively. For quantification of mycobacterial sputum load, we found a correlation between Xpert DNA amplification cycle thresholds, time to positivity, and microscopy smear grade. The best correlation was found between Xpert and time to positivity (
r
= 0.54), which were both correlated with smear microscopy with
r
values equal to −0.40 and −0.48, respectively. We conclude that MTBDR and Xpert are suitable screening tools for determining rifampin resistance in sputum microscopy smear-positive patients before participation in tuberculosis trials. Xpert should be further explored as a surrogate measurement for sputum mycobacterial load.
Controlled Comparison of BacT/Alert MB System, Manual Myco/F Lytic Procedure, and Isolator 10 System for Diagnosis of Mycobacterium tuberculosis Bacteremia
Authors: Crump John A. , Morrissey Anne B. , Ramadhani Habib O. , Njau Boniface N. , Maro Venance P. , Reller L. Barth
Published: June 2011

We compared the performance of the BacT/Alert MB system, that of the manual Bactec Myco/F Lytic procedure, and that of the Isolator 10 lysis-centrifugation system in the detection of
Mycobacterium tuberculosis
bacteremia. Mean times to detection were 16.4 days for BacT/Alert MB versus 20.0 days for Myco/F Lytic, 16.5 days for BacT/Alert MB versus 23.8 days for Isolator 10, and 21.1 days for Bactec Myco/F Lytic versus 22.7 days for Isolator 10. There were no significant differences in yields. The mean (range) magnitude of mycobacteremia was 30.0 (0.4, 90.0) CFU/ml and was correlated with the time to positivity in the BacT/Alert MB system (
r
= −0.4920).
M. tuberculosis
bacteremia was detected more rapidly in a continuously monitored liquid blood culture system, but the mean time to positivity exceeded 3 weeks.
Alpha-internexin expression in gliomas: relationship with histological type and 1p, 19q, 10p and 10q status
Authors: Durand Karine , Guillaudeau Angélique , Pommepuy Isabelle , Mesturoux Laura , Chaunavel Alain , Gadeaud Emilie , Porcheron Marion , Moreau Jean-Jacques , Labrousse François
Published: June 2011

Background

Thealpha-internexin(INA) gene encodes an intermediate filament involved in neurogenesis and maps in 10q24.33. A strong INA protein expression has been reported in oligodendroglial tumours and was associated with 1p19q deletion. To assess the relevance of INA immunohistochemistry in glioma typing, this paper studied the relationship between INA expression, histological type, genomic status and patient outcome.

Methods

The study analysed INA, nestin, Olig2 and p53 expression, loss of heterozygosity of microsatellite markers from telomere to centromere of 10p, 10q, 1p and 19q chromosomes andepidermal growth factor receptorgene (EGFR) amplification in 40 gliomas (five astrocytomas, 12 oligodendrogliomas, 11 oligoastrocytomas, 12 glioblastomas). INA expression was scored as absent, weak (<10% of labelled tumour cells) or strong (>10%).

Results

Oligodendrogliomas showed strong INA and Olig2 expression, and 1p19q whole loss of heterozygosity (wLOH). Astrocytomas and glioblastomas were characterised by no or weak INA expression, high p53 and nestin expression, 10p10q wLOH, andepidermal growth factor receptoramplification. Most oligoastrocytomas had characteristics of astrocytic tumours. All tumours with strong INA expression retained the 10q chromosome arm and, except for one, had a 1p19q wLOH status. However, despite a strong link between INA expression, 1p19q wLOH and 10q retention, discrepancies were observed in 10% of cases. The presence of INA expression, whether weak or strong, was related to a better prognosis.

Conclusion

INA expression study can be helpful for glioma typing and prognosis determination in combination with other markers. Nevertheless, INA immunohistochemistry cannot replace the genomic analysis to determine 1p19q and 10p10q status.
The glue ear ‘epidemic’: a historical perspective
Authors: Alderson David
Published: June 2011

This paper explores the historical context of the dramatic rise in surgery for glue ear in the mid-20th century, and questions the published assertion that this represented a manufactured ‘epidemic’. In examining historical sources, the reader's theoretical viewpoint greatly influences their conclusions: the sustained rise in treatment for glue ear may be seen as the advance of science in a golden age or the resistance of insular professionals to reason in the light of new scientific study methods. Current views on the practice of medicine, consumerism, science and standardisation, rationing and the nature of ‘truth’ all affect the way that we see this period. Technological advances clearly allowed better diagnosis and more effective treatment, but these did not appear to drive an ‘epidemic’, rather they were developed to meet the pre-existing challenges of otological practice. The proposition that an ‘epidemic’ was created does not appear to have any solid grounding. Society's perception of what constitutes disease and what needs treatment may have evolved, but the prevalence of other important diseases changed dramatically over this time period, and a real change in the epidemiology of glue ear cannot be dismissed. In defining the case for and against surgical treatment, a solely positivist, quantitative worldview cannot give us a complete picture of benefit and risk to individuals, families and society at large.
EFFECT OF TRANSMISSION FUNCTION OF CASCADED MULTILAYER MEDIUM THIN FILM FILTER ON Er–Yb CO-DOPED WAVEGUIDE AMPLIFIERS
Authors: CHEN HAIYAN
Published: June 2011

Modeling and amplification of erbium–ytterbium co-doped phosphate glass waveguide amplifier with a cascaded multilayer medium thin film filter is investigated theoretically. This proposed filter consists of some different filtering unit cells with different central wavelength and bandwidth, and each cell can suppress certain peak gain at a specific wavelength. The intrinsical gain spectrum of amplifier is obtained by solving a set of rate and power propagation equations, the effect of transmittance spectrum of thin film filter on flattening gain is discussed, and the transmission function of cascaded multilayer medium thin film filter is obtained.
THE EFFECT OF FINE ALUMINA TYPE ON COMPOSITION OF IN SITU SPINEL FORMATION IN ALUMINA-MAGNESIA CASTABLES
Authors: PAGHANDEH M. , MONSHI A. , EMADI R.
Published: June 2011

Three types of low cement castables (LCC) were prepared from 5% reactive alumina ( R 5), 5% calcined alumina ( A 5) and equal proportions of 2.5% (AR). The nest of the composition was fine bauxite (0–1 mm, 57%), coarse bauxite (1–3 mm, 20%), calcined magnesia (5%), secar 71 refractory cemet (7%) and microsilica (1%). By the addition of 5% water, castables were moulded, aged, dried and fired to 1400°C for 2 h. XRD studies showed higher amount of in situ spinel formation in A 5. The lattice constants of spinels in A 5, AR and R 5 were, respectively, 8.0348, 8.0688 and 8.0847 Å. This accounted for respectively alumina rich, stochiometry and magnesia rich spinels. Since calcined alumina is cheaper, produce higher amounts of spinel with the aid of alumina from the aggregate of bauxite and the binder of cement, and alumina rich spinel has better corrosion resistance properties, use of calcined alumina is recommended in LCC.
IMPULSIVE SYNCHRONIZATION AND ITS IMPLEMENTATION IN CHEN–LEE SYSTEMS
Authors: TAM LAP-MOU , LAO SENG-KIN , SHEU LONG-JYE , CHEN HSIEN-KENG
Published: June 2011

The impulsive synchronization of two chaotic Chen–Lee systems was investigated in this paper. Based on Lyapunov's direct method, sufficient conditions for the global exponential synchronization and global asymptotical synchronization were derived. Further, the theoretical results were verified by a numerical simulation. In addition, the impulsive synchronization of two chaotic Chen–Lee systems was also implemented using an electronic circuit.
ANALYTICAL TREATMENT OF SOME PARTIAL DIFFERENTIAL EQUATIONS ARISING IN MATHEMATICAL PHYSICS BY USING THEExp-FUNCTION METHOD
Authors: DEHGHAN MEHDI , MANAFIAN JALIL , SAADATMANDI ABBAS
Published: June 2011

The Exp -function method with the aid of symbolic computational system can be used to obtain the generalized solitary solutions and periodic solutions for nonlinear evolution equations arising in mathematical physics. In this paper, we study the analytic treatment of the Zakharov–Kuznetsov (ZK) equation, the modified ZK equation, and the generalized forms of these equations. Exact solutions with solitons and periodic structures are obtained.
INFLUENCE OF CRITICAL CURRENT DENSITY ON MAGNETIC FORCE OF HTSC BULK ABOVE PMR WITH 3D-MODELING NUMERICAL SOLUTIONS
Authors: LU YIYUN , LU BINGJUAN , GE YUNWANG , CHEN WENQING
Published: June 2011

Numerical electromagnetic field simulations of high-temperature superconductors (HTSC) bulk were carried out to calculate the magnetic force between the HTSC bulk and the permanent magnet railway (PMR). A 3D-modeling numerical calculation method is proposed using the finite element method. The model is formulated with the magnetic field vector (H-method). The resulting code was written with FORTRAN language. The electric field intensity E and the current density J constitutive relation of HTSC were described with E–J power law. The Kim macro-model is used to describe critical current density Jc of HTSC bulk. Two virtual HTSC bulks were used to solve the critical current density Jc anisotropic properties of HTSC materials. A superconducting levitation system composed of one HTSC bulk and PMR is successfully investigated using the proposed method. By this method, the influence of critical current density on magnetic levitation force of the superconducting levitation system is mathematically studied.
MAGNETIC SUSCEPTIBILITY OF GRAPHENE BY GAUSSIAN CORRECTION
Authors: HE PEISONG
Published: June 2011

In the present paper, we compute the magnetic susceptibility of graphene by using Gaussian correction. The collective excitations away from Fermi points of graphene are gapless, chiral fermions, with linear dispersion. The system is modeled as N massless Dirac fermions in two spatial dimensions interacting with 1/r Coulomb interactions. We find that the magnetic susceptibility is suppressed by the interaction between these collective excitations. And it has ln T correction due to the long-ranged Coulomb interaction, which is different from Landau Fermi liquid theory.
EFFECT OF TIME-DELAY ON A PREY–PREDATOR MODEL WITH MICROPARASITE INFECTION IN THE PREDATOR
Authors: PATHAK SWETA , MAITI ALAKES , BERA SHYAM PADA
Published: June 2011

To increase a prey population that is attacked by a predator it is more convenient and economical to choose the living organisms to control the predator. In this paper, the dynamical behaviors of a prey–predator model with microparasitic infection in the predator have been discussed. In this epidemiological model the microparasite is horizontally transmitted and attacks the predator population only. The infected population does not recover or become immune. The dynamical characteristics of the system are studied through mathematical analyses. The role of discrete time-delay has been discussed to show that time-delay can induce instability and oscillation. Numerical simulations are carried out. Biological implications have been discussed.
AN INTEGRATED MODEL USING WAVELET DECOMPOSITION AND LEAST SQUARES SUPPORT VECTOR MACHINES FOR MONTHLY CRUDE OIL PRICES FORECASTING
Authors: BAO YEJING , ZHANG XUN , YU LEAN , LAI KIN KEUNG , WANG SHOUYANG
Published: June 2011

In this paper, a hybrid model integrating wavelet decomposition and least squares support machines (LSSVM) is proposed for crude oil price forecasting. In this model, the Haar à trous wavelet transform is first selected to decompose an original time series into several sub-series with different scales. Then the LSSVM is used to predict each sub-series. Subsequently, the final oil price forecast is obtained by reconstructing the results of the sub-series forecasts. The experimental results show that the integrated model, based on multi-scale wavelet decomposition, outperforms the traditional single-scale models. Furthermore, the proposed hybrid model is the best among all the models compared in this study. To fully integrate the advantages of several models, a combined forecasting model is presented. The study shows that the combined forecasting model is clearly better than any individual model for crude oil price forecasting.
ON VARIOUS QUANTITATIVE APPROACHES FOR PRICING AMERICAN OPTIONS
Authors: ZHU SONG-PING
Published: June 2011

In this paper, a comprehensive review of the valuation of American options is presented. Various approaches to pricing American option contracts are discussed, with the pros and cons of each being briefly outlined. The paper aims to provide a literature review for those who are interested in this very fundamental research, that provides a basis for pricing any American-style derivatives.
Progress in In Situ X-Ray Tomographic Microscopy of Liquid Water in Gas Diffusion Layers of PEFC
Authors: Eller Jens , Rosén Tomas , Marone Federica , Stampanoni Marco , Wokaun Alexander , Büchi Felix N.
Published: June 2011

Water management is an important factor for optimizing polymer electrolyte fuel cells (PEFC) under high current density conditions as required for the automotive application. The characteristics of the local liquid saturation of the gas diffusion layer (GDL) is of particular interest. Here we report on the development of in-situ X-ray tomographic microscopy (XTM) with a pixel sizes in the order of 2 μm and sensitivity for carbon and liquid water for the quantitative analysis of liquid water in GDLs. In-situ XTM of PEFC is a major experimental challenge. A complete cell needs to be operated under realistic conditions in the constraint space of the small field of view on the beamline sample stage. Further phase segmentation of the images is required to successfully analyze the quantitative properties of the different phases. For this a workflow, applying differential images between dry and wet structures has been developed. Cells with Toray TGP-H-060 GDLs were analyzed in-situ. Droplets that appear on the GDL surface are connected to a significant water structure inside the GDL. Further the water cluster size distribution in the GDL shows that while small droplets (<100 pl) are numerous, most of the water is contained in few larger clusters.
Osmoregulatory defect in adult mice associated with deficient prenatal expression of six2
Authors: Somponpun S. Jack , Wong Brittany , Hynd Thomas E. , Fogelgren Benjamin , Lozanoff Scott
Published: June 2011

Suboptimal kidney development resulting from a genetic deficit in nephron number can have lifelong consequences that may lead to cardiorenal complications upon exposure to secondary insults in later life. To determine whether the inherited reduced renal reserve compromises the ability to handle osmotic stress in the adult animal, we challenged the heterozygous 3H1 Brachyrrhine ( Br/+) mouse, which displays heritable renal hypoplasia associated with reduced embryonic six2 expression, to a solution of 2% NaCl for 5 days or to fluid restriction for 48 h. Blood chemistry, fluid intake, and physiological parameters, including renal measurements, were determined. Systemic hypertonicity by prolonged salt loading led to significant increases in plasma osmolality and plasma Na+, along with polydipsia and polyuria, with a significant urine-concentrating defect that was resistant to DDAVP treatment in the adult Br/+ mouse compared with wild-type littermates. The Br/+ mouse also developed a significant increase in blood urea nitrogen at baseline that was further elevated when 2% NaCl was given. Fluid restriction for 48 h further enhanced plasma osmolality and plasma Na+ responses, although the Br/+ mouse was evidently able to produce a small amount of concentrated urine at this time. Hypothalamic c-Fos expression was appropriately activated in the Br/+ mouse in response to both osmotic challenges, indicating an intact central neuroendocrine pathway that was not affected by the lack of congenital six2 expression. Collectively, our results demonstrate impaired osmoregulatory mechanisms consistent with chronic renal failure in the Br/+ mouse and indicate that six2 haploinsufficiency has a direct effect on postnatal fluid and electrolyte handling associated with fluid imbalance.
A new mechanism for antiepileptic drug action: vesicular entry may mediate the effects of levetiracetam
Authors: Meehan Anna L. , Yang Xiaofeng , McAdams Brian D. , Yuan LiLian , Rothman Steven M.
Published: June 2011

Levetiracetam (LEV) is one of the most commonly prescribed antiepileptic drugs, but its mechanism of action is uncertain. Based on prior information that LEV binds to the vesicular protein synaptic vesicle protein 2A and reduces presynaptic neurotransmitter release, we wanted to more rigorously characterize its effect on transmitter release and explain the requirement for a prolonged incubation period for its full effect to manifest. During whole cell patch recordings from rat hippocampal pyramidal neurons in vitro, we found that LEV decreased synaptic currents in a frequency-dependent manner and reduced the readily releasable pool of vesicles. When we manipulated spontaneous activity and stimulation paradigms, we found that synaptic activity during LEV incubation alters the time at which LEV's effect appears, as well as its magnitude. We believe that synaptic activity and concomitant vesicular release allow LEV to enter recycling vesicles to reach its binding site, synaptic vesicle protein 2A. In support of this hypothesis, a vesicular “load-unload” protocol using hypertonic sucrose in the presence of LEV quickly induced LEV's effect. The effect rapidly disappeared after unloading in the absence of LEV. These findings are compatible with LEV acting at an intravesicular binding site to modulate the release of transmitter and with its most marked effect on rapidly discharging neurons. Our results identify a unique neurobiological explanation for LEV's highly selective antiepileptic effect and suggest that synaptic vesicle proteins might be appropriate targets for the development of other neuroactive drugs.
Facial injections of pruritogens or algogens elicit distinct behavior responses in rats and excite overlapping populations of primary sensory and trigeminal subnucleus caudalis neurons
Authors: Klein Amanda , Carstens Mirela Iodi , Carstens E.
Published: June 2011

In the present study, we investigated whether intradermal cheek injection of pruritogens or algogens differentially elicits hindlimb scratches or forelimb wipes in Sprague-Dawley rats, as recently reported in mice. We also investigated responses of primary sensory trigeminal ganglion (TG) and dorsal root ganglion (DRG) cells, as well as second-order neurons in trigeminal subnucleus caudalis (Vc), to pruritic and algesic stimuli. 5-HT was the most effective chemical to elicit dose-dependent bouts of hindlimb scratches directed to the cheek, with significantly less forelimb wiping, consistent with itch. Chloroquine also elicited significant scratching but not wiping. Allyl isothiocyanate (AITC; mustard oil) elicited dose-dependent wiping with no significant scratching. Capsaicin elicited equivalent numbers of scratch bouts and wipes, suggesting a mixed itch and pain sensation. By calcium imaging, ∼6% of cultured TG and DRG cells responded to 5-HT. The majority of 5-HT-sensitive cells also responded to chloroquine, AITC, and/or capsaicin, and one-third responded to histamine. Using a chemical search strategy, we identified single units in Vc that responded to intradermal cheek injection of 5-HT. Most were wide dynamic range (WDR) or nociceptive specific (NS), and a few were mechanically insensitive. The large majority additionally responded to AITC and/or capsaicin and thus were not pruritogen selective. These results suggest that primary and second-order neurons responsive to pruritogens and algogens may utilize a population coding mechanism to distinguish between itch and pain, sensations that are behaviorally manifested by distinct hindlimb scratching and forelimb wiping responses.
The impact of brief exposure to high contrast on the contrast response of neurons in primate lateral geniculate nucleus
Authors: Camp Aaron J. , Cheong Soon K. , Tailby Chris , Solomon Samuel G.
Published: June 2011

Prolonged exposure to an effective stimulus generally reduces the sensitivity of neurons early in the visual pathway. Yet eye and head movements bring about frequent changes in the retinal image, and it is less clear that exposure to brief presentations will produce similar desensitization. To address this, we made extracellular recordings from single neurons in the lateral geniculate nucleus of anesthetized marmosets, a New World primate. We measured the contrast response for drifting gratings before and after 0.5-s exposure to a high-contrast drifting grating, a stationary grating, or a blank screen. Prior exposure to the drifting grating reduced the contrast sensitivity of cells in the magnocellular pathway, on average by 23%; this reduction remained strong when the adapting and test stimuli were separated by 0.4 s. Exposure to a stationary grating of the preferred spatial phase did not change the contrast response; exposure to the opposite spatial phase did. None of the brief adaptors reduced the sensitivity of parvocellular cells. We conclude that brief periods of high contrast, such as those that would be expected to occur during a normal visual fixation, are sufficient to reduce the sensitivity of magnocellular-pathway cells.
Modulation of shifting receptive field activity in frontal eye field by visual salience
Authors: Joiner Wilsaan M. , Cavanaugh James , Wurtz Robert H.
Published: June 2011

In the monkey frontal eye field (FEF), the sensitivity of some neurons to visual stimulation changes just before a saccade. Sensitivity shifts from the spatial location of its current receptive field (RF) to the location of that field after the saccade is completed (the future field, FF). These shifting RFs are thought to contribute to the stability of visual perception across saccades, and in this study we investigated whether the salience of the FF stimulus alters the magnitude of FF activity. We reduced the salience of the usually single flashed stimulus by adding other visual stimuli. We isolated 171 neurons in the FEF of 2 monkeys and did experiments on 50 that had FF activity. In 30% of these, that activity was higher before salience was reduced by adding stimuli. The mean magnitude reduction was 16%. We then determined whether the shifting RFs were more frequent in the central visual field, which would be expected if vision across saccades were only stabilized for the visual field near the fovea. We found no evidence of any skewing of the frequency of shifting receptive fields (or the effects of salience) toward the central visual field. We conclude that the salience of the FF stimulus makes a substantial contribution to the magnitude of FF activity in FEF. In so far as FF activity contributes to visual stability, the salience of the stimulus is probably more important than the region of the visual field in which it falls for determining which objects remain perceptually stable across saccades.
Recruitment in Swarm-Founding Wasps:Polybia occidentalisDoes not Actively Scent-Mark Carbohydrate Food Sources
Authors: Taylor Benjamin J. , Nordheim Erik V. , Schueller Teresa I. , Jeanne Robert L.
Published: June 2011

Scent marking food resources is expected to enhance foraging efficiency reducing search time. Many social bees exhibit this behavior, but scent-marking is absent in social wasps, except forVespa mandarinia. We tested for scent marking in the swarm-founding wasp,Polybia occidentalis. This wasp has moderately large colonies and utilizes resources that are concentrated in time and space, making scent marking profitable. Also, this wasp uses chemical markings to lead nestmates to a new nest site during swarm emigration, making it possible that it could use the same behavior to recruit nestmates to a food source. Foragers from 11 colonies were given a choice between a previously visited feeder and an unvisited one, both containing a rich, unscented sucrose solution. There was no difference in the number of visits to the two treatments. However, some individuals chose the feeder on one side more often. We conclude that foragers of this species of wasp do not use odor marks left behind by nestmates to find food, but they do exhibit the tendency, when returning to a food source that has not been depleted, to choose a resource based on its relative position, presumably by using visual cues.
Recent Progress in Hydrogen Electrocatalysis
Authors: Quaino P. , Santos E. , Soldano G. , Schmickler W.
Published: June 2011

Recently, we have proposed a unified model for electrochemical electron transfer
reactions which explicitly accounts for the electronic structure of the electrode.
It provides a framework describing the whole course of bond‐breaking electron
transfer, which explains catalytic effects caused by the presence of surface d bands.
In application on real systems, the parameters of this model—interaction strengths,
densities of states, and energies of reorganization—are obtained from density
functional theory (DFT). In this opportunity, we review our main achievements in applying the theory of
electrocatalysis. Particularly, we have focused on the electrochemical adsorption
of a proton from the solution—the Volmer reaction—on a variety of systems of
technological interest, such as bare single crystals and nanostructured surfaces. We
discuss in detail the interaction of the surface metal d band with the valence orbital
of the reactant and its effect on the catalytic activity as well as other aspects that
influence the surface‐electrode reactivity such as strain and chemical factors.
IL-8 Signaling Plays a Critical Role in the Epithelial–Mesenchymal Transition of Human Carcinoma Cells
Authors: Fernando Romaine I. , Castillo Marianne D. , Litzinger Mary , Hamilton Duane H. , Palena Claudia
Published: June 2011

The switch of tumor cells from an epithelial to a mesenchymal-like phenotype [designated as epithelial-to-mesenchymal transition (EMT)] is known to induce tumor cell motility and invasiveness, therefore promoting metastasis of solid carcinomas. Although multiple studies have focused on elucidating the signaling events that initiate this phenotypic switch, there has been so far no characterization of the pattern of soluble mediators released by tumor cells undergoing EMT, and the potential impact that this phenotypic switch could have on the remodeling of the tumor microenvironment. Here we show that induction of EMT in human carcinoma cells via overexpression of the transcription factor Brachyury is associated with enhanced secretion of multiple cytokines, chemokines, and angiogenic factors and, in particular, with the induction of the IL-8/IL-8R axis. Our results also indicate the essential role of interleukin 8 (IL-8) signaling for the acquisition and/or maintenance of the mesenchymal and invasive features of Brachyury-overexpressing tumor cells and show that IL-8 secreted by tumor cells undergoing EMT could potentiate tumor progression by inducing adjacent epithelial tumor cells into EMT. Altogether, our results emphasize the potential role of EMT in the modulation of the tumor microenvironment via secretion of multiple soluble mediators and suggest that IL-8 signaling blockade may provide a means of targeting mesenchymal-like, invasive tumor cells. Cancer Res; 71(15); 5296–306. ©2011 AACR.
Peloruside- and Laulimalide-Resistant Human Ovarian Carcinoma Cells Have βI-Tubulin Mutations and Altered Expression of βII- and βIII-Tubulin Isotypes
Authors: Kanakkanthara Arun , Wilmes Anja , O'Brate Aurora , Escuin Daniel , Chan Ariane , Gjyrezi Ada , Crawford Janet , Rawson Pisana , Kivell Bronwyn , Northcote Peter T. , Hamel Ernest , Giannakakou Paraskevi , Miller John H.
Published: June 2011

Peloruside A and laulimalide are potent microtubule-stabilizing natural products with a mechanism of action similar to that of paclitaxel. However, the binding site of peloruside A and laulimalide on tubulin remains poorly understood. Drug resistance in anticancer treatment is a serious problem. We developed peloruside A- and laulimalide-resistant cell lines by selecting 1A9 human ovarian carcinoma cells that were able to grow in the presence of one of these agents. The 1A9-laulimalide resistant cells (L4) were 39-fold resistant to the selecting agent and 39-fold cross-resistant to peloruside A, whereas the 1A9-peloruside A resistant cells (R1) were 6-fold resistant to the selecting agent while they remained sensitive to laulimalide. Neither cell line showed resistance to paclitaxel or other drugs that bind to the taxoid site on β-tubulin nor was there resistance to microtubule-destabilizing drugs. The resistant cells exhibited impaired peloruside A/laulimalide-induced tubulin polymerization and impaired mitotic arrest. Tubulin mutations were found in the βI-tubulin isotype, R306H or R306C for L4 and A296T for R1 cells. This is the first cell-based evidence to support a β-tubulin–binding site for peloruside A and laulimalide. To determine whether the different resistance phenotypes of the cells were attributable to any other tubulin alterations, the β-tubulin isotype composition of the cells was examined. Increased expression of βII- and βIII-tubulin was observed in L4 cells only. These results provide insight into how alterations in tubulin lead to unique resistance profiles for two drugs, peloruside A and laulimalide, that have a similar mode of action. Mol Cancer Ther; 10(8); 1419–29. ©2011 AACR.
Anxiety and Depression in Cardiac Patients: Age Differences and Comparisons with the General Population
Authors: Hinz Andreas , Kittel Jörg , Karoff Marthin , Daig Isolde
Published: June 2011

Background: Anxiety and depression are often found in cardiac patients, but also in the general population. Therefore, evaluation of these symptoms in patients requires a comparison with norm values. The purpose of this study was to explore differences between cardiac patients and the general population in age dependency of anxiety and depression, and to discuss possible reasons for these differences. Methods: A sample of German cardiac patients (n = 2,696) and a sample of the German general population (n = 2,037) were tested using the Hospital Anxiety and Depression Scale (HADS). Results: While we confirmed a linear age trend of anxiety and depression in the general population, we observed an inverted U-shaped age dependency in the patient sample. Young patients are especially affected by anxiety and depression. Five items of the HADS that mainly contributed to the age differences were identified. Formal characteristics of these 5 items could not explain the age differences. Concerning the meaning of the items, however, most of the items refer to worrying about the future. Conclusions: The relatively low rates of anxiety and depression in older patients (compared with the general population) indicate that adaptation processes took place, which should be taken into account in studies concerning the psychological status of patients. Young patients need special attention when dealing with mental distress.
Expression and Functional Analysis of Dkk1 during Early Gonadal Development
Authors: Combes A.N. , Bowles J. , Feng C.-W. , Chiu H.S. , Khoo P.-L. , Jackson A. , Little M.H. , Tam P.P.L. , Koopman P.
Published: June 2011

WNT signalling plays a central role in mammalian sex determination by promoting ovarian development and repressing aspects of testis development in the early gonad. Dickkopf homolog 1 (DKK1) is a WNT signalling antagonist that plays critical roles in multiple developmental systems by modulating WNT activity. Here, we examined the role of DKK1 in mouse sex determination and early gonadal development. Dkk1 mRNA was upregulated sex-specifically during testis differentiation, suggesting that DKK1 could repress WNT signalling in the developing testis. However, we observed overtly normal testis development in Dkk1-null XY gonads, and found no significant upregulation of Axin2 or Sp5 that would indicate increased canonical WNT signalling. Nor did we find significant differences in expression of key markers of testis and ovarian development. We propose that DKK1 may play a protective role that is not unmasked by loss-of-function in the absence of other stressors.
Methylation Status of cMHM and Expression of Sex-Specific Genes in Adult Sex-Reversed Female Chickens
Authors: Yang X. , Zheng J. , Qu L. , Chen S. , Li J. , Xu G. , Yang N.
Published: June 2011

The objective of the current study was to analyze the methylation status of the chicken male hypermethylation (cMHM) region and mRNA expression levels of sex-dependent genes in adult female-to-male sex-reversed chickens. Sex reversal from genetic females into phenotypic males was induced by injection of 1.0 mg fadrozole, an aromatase inhibitor, into fertilized eggs at 3.0 days of incubation. Birds aged 30 weeks were classified into 4 groups according to the histological structure of their gonads and the natural logarithm of the ratio of testosterone to estradiol in serum, namely standard females, slightly sex-reversed females with left ovotestes, highly sex-reversed females with left testes, and standard males. The results showed that methylation of the cMHM amplicon was lowest in the ovaries of standard females and highest in testes of standard males. Methylation levels were significantly higher in the left testes of highly sex-reversed females than in the left ovotestes of slightly sex-reversed females (p < 0.05). Expression analysis of 9 sex-specific genes in the gonad indicated that DMRT1 and HINTZ had a similar expression pattern, with significantly higher levels in standard males as compared to standard females, slightly and highly sex-reversed females (p < 0.05). Expression of FOXL2, AMH, P450arom, SF1, and ERα was obviously higher in standard females than in standard males, slightly and highly sex-reversed females (p < 0.05). Expression of SOX9 in standard females was similar to that in slightly sex-reversed females and lower than in highly sex-reversed females and standard males (p < 0.05).