bluuebunny/crossref_metadata_2025 huggingface dataset:
Primary immunodeficiencies of pattern recognition receptors
Authors: Netea M. G. , van de Veerdonk F. L. , van der Meer J. W. M.
Published: April 2013

Primary immunodeficiencies (PIDs) are severe defects in the capacity of the host to mount a proper immune response, and are characterized by an increased susceptibility to infections. Although classical immunodeficiencies have been characterized based on broad defects in cell populations (e.g. T/B cells or polymorphonuclear leukocytes) or humoral factors (e.g. antibodies or complement), specific immune defects based on well‐defined molecular targets have been described more recently. Among these, genetic defects in pattern recognition receptors (PRRs), leading to impaired recognition of invading pathogens by the innate immune system, play an important role in specific defects against human pathogens. Defects have been described in three of the major families of PRRs: the Toll‐like receptors, the C‐type lectin receptors and the nucleotide‐binding domain leucine‐rich repeat‐containing receptors. By contrast, no defects in the intracellular viral receptors of the RigI helicase family have been described to date. Defects in the PRRs show a broad variation in severity, have a narrow specificity for certain classes of pathogens, and often decrease in severity with age; these characteristics distinguish them from other forms of PIDs. Their discovery has led to important insights into the pathophysiology of infections, and may offer potential novel therapeutic targets for immunotherapy.
Use of a Formal Assessment Instrument for Evaluation of Veterinary Student Surgical Skills
Authors: Schnabel Lauren V. , Maza Paul S. , Williams Kimberly M. , Irby Nita L. , McDaniel Carolyn M. , Collins Brian G.
Published: April 2013

Objectives

To (1) evaluate the design and use of a global rating scale assessment instrument in veterinary medical education and; (2) examine the effectiveness of 2 surgical techniques courses for improving the surgical skills of veterinary students.

Study Design

Instrument development; observational; survey‐based.

Sample Population

Students (n = 16) registered for 2 elective surgical techniques courses were enrolled on a volunteer basis.

Methods

A 5‐point global rating scale instrument was designed for the evaluation of 12 basic surgical skills by faculty evaluators and used to obtain student start and end scores during the courses. Upon conclusion of the courses, students completed a survey from which their opinions on their improvement as well as their desire for feedback were obtained.

Results

All authors agreed the instrument was easy to use. As groups, 3rd year students, 4th year students, and all students combined had significantly higher total skill scores at the end of the courses compared to the start of the courses. Individually, 10 students (63%) had significant improvement in surgical skills as a result of their participation in the courses: 4 (100%) 3rd year and 6 (50%) 4th year students. Student survey responses revealed a strong desire for feedback as well as support of formal assessment methods. Only weak agreement was found between student opinions on their improvement and the authors' assessment scores.

Conclusions

Assessment instruments are useful for (1) student evaluation and (2) for providing students with feedback on their surgical skills.
Using remote underwater video to estimate freshwater fish species richness
Authors: Ebner B. C. , Morgan D. L.
Published: April 2013

Species richness records from replicated deployments of baited remote underwater video stations (BRUVS) and unbaited remote underwater video stations (UBRUVS) in shallow (<1 m) and deep (>1 m) water were compared with those obtained from using fyke nets, gillnets and beach seines. Maximum species richness (14 species) was achieved through a combination of conventional netting and camera‐based techniques. Chanos chanos was the only species not recorded on camera, whereas Lutjanus argentimaculatus, Selenotoca multifasciata and Gerres filamentosus were recorded on camera in all three waterholes but were not detected by netting. BRUVSs and UBRUVSs provided versatile techniques that were effective at a range of depths and microhabitats. It is concluded that cameras warrant application in aquatic areas of high conservation value with high visibility. Non‐extractive video methods are particularly desirable where threatened species are a focus of monitoring or might be encountered as by‐catch in net meshes.
Triglyceride‐cholesterol imbalance across lipoprotein subclasses predicts diabetic kidney disease and mortality in type 1 diabetes: the FinnDiane Study
Authors: Mäkinen V.‐P. , Soininen P. , Kangas A. J. , Forsblom C. , Tolonen N. , Thorn L. M. , Viikari J. , Raitakari O. T. , Savolainen M. , Groop P.‐H. , Ala‐Korpela M. ,   Finnish Diabetic Nephropathy Study Group
Published: April 2013

Background

Circulating cholesterol (C) and triglyceride (TG) levels are associated with vascular injury in type 1 diabetes (T1DM). Lipoproteins are responsible for transporting lipids, and alterations in their subclass distributions may partly explain the increased mortality in individuals with T1DM.

Design and subjects

A cohort of 3544 individuals with T1DM was recruited by the nationwide multicentre FinnDiane Study Group. At baseline, six very low‐density lipoprotein VLDL, one intermediate‐density lipoprotein IDL, three low‐density lipoprotein LDL and four higher high‐density lipoprotein HDL subclasses were quantified by proton nuclear magnetic resonance spectroscopy. At follow‐up, the baseline data were analysed for incident micro‐ or macroalbuminuria (117 cases in 5.3 years), progression from microalbuminuria (63 cases in 6.1 years), progression from macroalbuminuria (109 cases in 5.9 years) and mortality (385 deaths in 9.4 years). Univariate associations were tested by age‐matched cases and controls and multivariate lipoprotein profiles were analysed using the self‐organizing map (SOM).

Results

TG and C levels in large VLDL were associated with incident albuminuria, TG and C in medium VLDL were associated with progression from microalbuminuria, and TG and C in all VLDL subclasses were associated with mortality. Large HDL‐C was inversely associated with mortality. Three extreme phenotypes emerged from SOM analysis: (i) low C (<3% mortality), (ii) low TG/C ratio (6% mortality), and (iii) high TG/C ratio (40% mortality) in all subclasses.

Conclusions

TG–C imbalance is a general lipoprotein characteristic in individuals with T1DM and high vascular disease risk.
Toxic neurofilamentous axonopathies– accumulation of neurofilaments and axonal degeneration
Authors: Llorens J.
Published: April 2013

A number of neurotoxic chemicals induce accumulation of neurofilaments in axonal swellings that appear at varying distances from the cell body. This pathology is associated with axonal degeneration of different degrees. The clinical manifestation is most commonly that of a mixed motor–sensory peripheral axonopathy with a disto‐proximal pattern of progression, as in cases of chronic exposure to n‐hexane and carbon disulphide. It has been demonstrated that protein adduct formation is a primary molecular mechanism of toxicity in these axonopathies, but how this mechanism leads to neurofilament accumulation and axonal degeneration remains unclear. Furthermore, little is known regarding the mechanisms of neurofilamentous axonopathy caused by 3,3′‐iminodipropionitrile, an experimental toxin that induces proximal axon swelling that is strikingly similar to that found in early amyotrophic lateral sclerosis. Here, we review the available data and main hypotheses regarding the toxic axonopathies and compare them with the current knowledge of the biological basis of neurofilament transport. We also review recent studies addressing the question of how these axonopathies may cause axonal degeneration. Understanding the mechanisms underlying the toxic axonopathies may provide insight into the relationship between neurofilament behaviour and axonal degeneration, hopefully enabling the identification of new targets for therapeutic intervention. Because neurofilament abnormalities are a common feature of many neurodegenerative diseases, advances in this area may have a wider impact beyond toxicological significance.
Regenerative medicine for the treatment of heart disease
Authors: Hansson E. M. , Lendahl U.
Published: April 2013

Heart failure is a major cause of mortality worldwide with a steady increase in prevalence. There is currently no available cure beyond orthotopic heart transplantation, which for a number of reasons is an option only for a small fraction of all patients. Considerable hope has therefore been placed on the possibility of treating a failing heart by replacing lost cardiomyocytes, either through transplantation of various types of stem cells or by boosting endogenous regenerative mechanisms in the heart. Here, we review the current status of stem and progenitor cell‐based therapies for heart disease. We discuss the pros and cons of different stem and progenitor cell types that can be considered for transplantation and describe recent advances in the understanding of how cardiomyocytes normally differentiate and how these cells can be generated from more immature cells ex vivo. Finally, we consider the possibility of activation of endogenous stem and progenitor cells to treat heart failure.
A Palaeolithic‐type diet causes strong tissue‐specific effects on ectopic fat deposition in obese postmenopausal women
Authors: Ryberg M. , Sandberg S. , Mellberg C. , Stegle O. , Lindahl B. , Larsson C. , Hauksson J. , Olsson T.
Published: April 2013

Objectives

Ectopic fat accumulation in liver and skeletal muscle may be an essential link between abdominal obesity, insulin resistance and increased risk of cardiovascular disease after menopause. We hypothesized that a diet containing a relatively high content of protein and unsaturated fat [mainly monounsaturated fatty acids (MUFAs)] but limited carbohydrates and saturated fat would reduce lipid content in liver and muscle and increase insulin sensitivity in postmenopausal women.

Subjects

Ten healthy, nonsmoking postmenopausal women with a body mass index (BMI) >27 (28–35) kg m−2 were included in the study.

Interventions

Participants were instructed to consume an ad libitum Palaeolithic‐type diet intended to provide approximately 30 energy percentage (E%) protein, 40 E% fat (mainly MUFAs) and 30 E% carbohydrate. Intramyocellular lipid (IMCL) levels in calf muscles and liver triglyceride levels were quantified using proton magnetic resonance spectroscopy (1H‐MRS) before and 5 weeks after dietary intervention. Insulin sensitivity was estimated by homoeostasis model assessment (HOMA) indices and the euglycaemic hyperinsulinaemic clamp technique.

Results

Mean energy intake decreased by 25% with a weight loss of 4.5 kg. BMI, waist and hip circumference, waist/hip ratio and abdominal sagittal diameter also decreased significantly, as did diastolic blood pressure (mean −7 mmHg), levels of fasting serum glucose, cholesterol, triglycerides, LDL/HDL cholesterol, apolipoprotein B (ApoB) and apolipoprotein A1 (ApoA1), urinary C‐peptide and HOMA indices. Whole‐body insulin sensitivity did not change. Liver triglyceride levels decreased by 49%, whereas IMCL levels in skeletal muscle were not significantly altered.

Conclusions

A modified Palaeolithic‐type diet has strong and tissue‐specific effects on ectopic lipid deposition in postmenopausal women.
Religion as a Commitment Device: The Economics of Political Islam
Authors: Roháč Dalibor
Published: April 2013

Why are religious parties so popular in the new and emerging democracies of the Middle East and North Africa? This paper offers an alternative to the traditional accounts that stress religiosity, the repressive nature of the previous regimes, poverty and underdevelopment, or Arab grievances against Israel. Instead, it outlines a rational choice‐based explanation, in which religious political parties are able to address the problem of credible commitment, ubiquitous in new democracies. Instead of having to rely on patronage as the only mechanism of making pre‐electoral commitments, Islamic parties are able to directly make credible promises about the supply of public goods. This is because they already have a history and a reputation, which both serve as channels of communication with the voters. Their reputation relies most importantly on a track record of providing social services in environments where governments have failed to do so. Furthermore, we argue that their religious nature makes them well equipped to overcome collective action problems.
Variance stabilization for computing and comparing grand mean waveforms inMEGandEEG
Authors: Matysiak Artur , Kordecki Wojciech , Sielużycki Cezary , Zacharias Norman , Heil Peter , König Reinhard
Published: April 2013

Grand means of time‐varying signals (waveforms) across subjects in magnetoencephalography (MEG) and electroencephalography (EEG) are commonly computed as arithmetic averages and compared between conditions, for example, by subtraction. However, the prerequisite for these operations, homogeneity of the variance of the waveforms in time, and for most common parametric statistical tests also between conditions, is rarely met. We suggest that the heteroscedasticity observed instead results because waveforms may differ by factors and additive terms and follow a mixed model. We propose to apply the asinh‐transformation to stabilize the variance in such cases. We demonstrate the homogeneous variance and the normal distributions of data achieved by this transformation using simulated waveforms, and we apply it to realMEGdata and show its benefits. The asinh‐transformation is thus an essential and useful processing step prior to computing and comparing grand mean waveforms inMEGandEEG.
Unilateral intraocular mastocytosis and anterior uveitis in a dog with subcutaneous mast cell tumors
Authors: Boostrom Brendan O. , Good Kathryn L. , Maggs David J. , Rebhun Robert B. , Johns Jennifer L. , Kent Michael S.
Published: April 2013

A 9‐year‐old male castratedScottish terrier was referred to the Radiation Oncology Service at theWilliamR.PritchardVeterinaryMedicalTeachingHospital for palliative radiation therapy of an incompletely excised, recurrent subcutaneous mast cell tumor (MCT) located over the right scapula, and surgical removal of a perianal MCT. Three weeks after initial presentation and prior to the fifth radiation treatment, the patient was presented with cloudiness of the left eye of 3–7 days duration. Ophthalmic consultation revealed 3+ aqueous flare with a dependent, swirling component filling approximately one‐third of the anterior chamber. Aqueocentesis was performed under general anesthesia. Cytology revealed mast cells with highly atypical morphology and considered most consistent with neoplasia. The patient died 7 months after pathologic diagnosis of MCT on the right shoulder and 2 months after the cytologic diagnosis of malignant mast cells in the left anterior chamber. To the authors' knowledge, this is the first report of intraocular involvement in a mammal with MCTs, described here as intraocular mastocytosis.
Complete Genome Sequence of the Hyperthermophilic Sulfate-Reducing Bacterium
Thermodesulfobacterium geofontis
OPF15
T
Authors: Elkins James G. , Hamilton-Brehm Scott D. , Lucas Susan , Han James , Lapidus Alla , Cheng Jan-Fang , Goodwin Lynne A. , Pitluck Sam , Peters Lin , Mikhailova Natalia , Davenport Karen W. , Detter John C. , Han Cliff S. , Tapia Roxanne , Land Miriam L. , Hauser Loren , Kyrpides Nikos C. , Ivanova Natalia N. , Pagani Ioanna , Bruce David , Woyke Tanja , Cottingham Robert W.
Published: April 2013

Thermodesulfobacterium geofontis
OPF15
T
(ATCC BAA-2454, JCM 18567) was isolated from Obsidian Pool, Yellowstone National Park, and grows optimally at 83°C. The 1.6-Mb genome sequence was finished at the Joint Genome Institute and has been deposited for future genomic studies pertaining to microbial processes and nutrient cycles in high-temperature environments.
Escape responses by jet propulsion in scallops
Authors: Guderley Helga E. , Tremblay Isabelle
Published: April 2013

The impressive swimming escape response of scallops uses a simple locomotor system that facilitates analysis of the functional relationships between its primary components. One large adductor muscle, two valves, the muscular mantle, and the rubbery hinge ligament are the basic elements allowing swimming by jet propulsion. Although these basic functional elements are shared among scallop species, the exact nature of the escape response varies considerably within and among species. Valve shape and density have opposing influences upon the capacity for swimming and the ease of attack by predators once captured. Patterns of muscle use can partly overcome the constraints imposed by shell characteristics. The depletion of muscle reserves during gametogenesis leads to a trade-off between escape response performance and reproductive investment. However, changes in muscle energetic status influence repeat performance more than initial escape performance. Escape response performance is influenced by habitat temperature and mariculture techniques. During scallop ontogeny, changes in susceptibility to predation and in reproductive investment may influence escape response capacities. These ontogenetic patterns are likely to vary with the longevity and maximal size of each species. Although the basic elements allowing swimming by jet propulsion are common to scallops, their exact use varies considerably among species.
A TIME-DOMAIN 1.0-V/0.8-MW 6-BIT 125 MS/S FLASH ADC IN 65 NM CMOS
Authors: HUANG GUANZHONG , LIN PINGFEN
Published: April 2013

A 6-bit low-voltage power-efficient flash analog-to-digital converter (ADC) is presented in this paper. The proposed ADC replaces the conventional voltage comparator with a new approach in the time-domain. The reference voltages and the analog input voltage are converted to digital signal in a form of different pulse widths by using a pulse-width-modulation (PWM) circuit. Consequently, the comparison is achieved by checking the sequence of the pulse rising edges rather than amplifying and latching the voltage difference. The total input capacitance of the proposed ADC is as small as tens of femto-farads, resulting in much less demand for the front-end buffer and the sampling switch. In addition, an implementation of the digital foreground calibration helps to get rid of the nonmonotonic comparison thresholds due to mismatch. The calibration operates with the adaptive comparison threshold by tuning the modulation level of the PWM. The intermediate Gray code conversion increases the bubble tolerance by 1LSB. This digital-circuit-heavily-involved ADC has been designed and simulated in a 65 nm CMOS process, achieving 35.24 dB signal-to-noise-and-distortion-ratio (SNDR) at a sampling rate of 125 MS/s while consuming 803 μW from 1 V power supply. As a result, the figure of merit (FoM) is as low as 136 fJ/conversion-step.
RAPIDITY AND ANGULAR DEPENDENCES OF SPECTRAL TEMPERATURES OF NEGATIVE PIONS PRODUCED IN 12C12C COLLISIONS AT 4.2A GeV/c
Authors: OLIMOV KHUSNIDDIN K. , HASEEB MAHNAZ Q. , HADI SAYYED A.
Published: April 2013

The average spectral temperatures of negative pions in 12 C 12 C collisions at 4.2A GeV/c were extracted from transverse momentum as well as scaled center-of-mass kinetic energy distributions for different intervals of rapidity and emission angle of π- in the center-of-mass system (cms) of 12 C 12 C collisions. The temperatures extracted from experimental spectra of negative pions were compared systematically with the corresponding temperatures deduced from spectra of π- calculated using Modified FRITIOF model. The dependence of the average spectral temperatures of negative pions on the rapidity and emission angle of π- in the cms of 12 C 12 C collisions at 4.2A GeV/c was analyzed.
INDUCED CHOQUET INTEGRALS OF 2-TUPLE LINGUISTIC INFORMATION
Authors: YANG WEI
Published: April 2013

The group decision making problem with inter-dependent or interactive attributes is studied. By using the Choquet integral and the inducing variables, we develop the induced 2-tuple correlated averaging (ITCA) operator, the generalized induced 2-tuple correlated averaging (GITCA) operator and the quasi-arithmetic induced 2-tuple correlated averaging (QITCA) operator. The characteristics of the proposed operators are that the evaluation values of decision makers are in linguistic arguments, the correlations among the elements can be reflected and the ordering of the arguments is based on other associated variables instead of their own values. The properties of these operators are studied and new multiple attribute decision making method based on the new operators is proposed. Finally, architecture material supplier selection problem is provided to illustrate the feasibility and efficiency of the proposed method.
A POSSIBILISTIC APPROACH TO INVESTMENT DECISION MAKING
Authors: ANZILLI LUCA
Published: April 2013

The concept of possibilistic mean value and variance of fuzzy numbers has been applied to investment decisions by using a nonlinear type of fuzzy numbers called adaptive fuzzy numbers. In this paper, by extending the notion of adaptive fuzzy number, we propose a more flexible methodology. Our aim is to allow decision maker more flexibility in dealing with ambiguity and uncertainty. To illustrate the use of our approach and its ability in dealing with ambiguity and imprecision we analyze, as an application, the fuzzy net present value of future cash flows and give some numerical results.
MULTI-ATTRIBUTE DECISION MAKING METHOD BASED ON POSSIBILITY VARIANCE COEFFICIENT OF TRIANGULAR INTUITIONISTIC FUZZY NUMBERS
Authors: WAN SHU-PING
Published: April 2013

Triangular intuitionistic fuzzy numbers (TIFNs) are a special case of intuitionistic fuzzy sets. The purpose of this paper is to develop a new decision making method based on possibility variance coefficient to solve the multi-attribute decision making (MADM) problems, in which the attribute values are in the form of TIFNs and the weight preference information is incomplete. The possibility mean, variance and standard deviation for a TIFN are introduced as well as the possibility variance coefficient. Hereby, a new method to rank TIFNs is given on the basis of the possibility variance coefficients. The bi-objective mathematical programming, which minimizes the possibility variance coefficients of membership and non-membership functions for alternative's overall attribute values, is constructed. Using the max-min method, two non-linear fractional programming models are transformed into the linear programming models through the Charnes and Cooper transformation. Thus, the Pareto optimal solution to the bi-objective mathematical programming can be derived by solving the single-objective programming model. The ranking order of alternatives is obtained according to the minimum possibility variance coefficients. A personal selection example is given to verify the developed method and to demonstrate its feasibility and effectiveness. The analysis of comparison with other method is also conducted.
GNR Production through Hydrogen Plasma Assisted CNT Unzipping
Authors: Mohammadi Somayyeh , Kolahdouz Esfahani Zahra , Darbari Sara , Mohajerzadeh Shams , Masoumi Nasser
Published: April 2013

In this work, we report a novel high yield hydrogen assisted unzipping method of multi-wall Carbon nanotubes. Vertical MWNTs are grown on a Silicon substrate at low temperature by a PE-CVD method using Methane or Acetylene gas. Vertically aligned CNTs are horizontally placed on another Silicon substrate through a combination of SF6 plasma exposure and mechanical rubbing. Horizontally placed CNTs are exposed to hydrogen plasma at 300-500ºC for several minutes. Plasma exposure results in longitudinal unzipping of Carbon nanotubes which, in turn, leads to graphene nano-sheets and Graphene nano-ribbon production in thick and thin diameter nano-tubes, respectively.
Electrical Transport of Single- and Double-Walled Carbon Nanotubes Functionalized with Monovalent Phenyl Groups
Authors: Bouilly Delphine , Cabana Janie , Martel Richard
Published: April 2013

We present a comprehensive study on the effect of monovalent functionalization on the electrical properties of carbon nanotubes, and discuss new strategies that combine extensive functionalization with good electrical conductivity. Many individual single- and double-walled carbon nanotubes (SWNTs and DWNTs) were characterized before and after functionalization with 4-bromophenyl grafts, and after defunctionalization by thermal annealing. Functionalization resulted in a reduction of the ON-state current by an order of magnitude or more in both metallic and semiconducting SWNTs. The OFF-state leak current increased by up to three orders of magnitude in semiconducting SWNTs. Graft bonding was reversible with a 770 K vacuum anneal, although some residual damage was left on the nanotube surface. Functionalization of DWNTs affected the outer wall similarly as for SWNTs, while the inner wall was left in pristine state. Functionalized-DWNTs devices can be operated through the inner wall with electrical performance as good as pristine SWNTs.
(Invited) Chemical Synthesis in Solution and Porphyrin Nanostructures on Surfaces - Similar Concepts, Different Results
Authors: Ryan Aoife A. , Cafolla Atillio A. , Senge Mathias O.
Published: April 2013

The chemistry of porphyrins is reaching out to more complex and ever larger polyporphyrin arrays. In solution the synthesis of porphyrin arrays is greatly aided by recent advances in organometallic chemistry which now allows the rational construction of selected tetrapyrrole scaffolds. Examples for these are unsymmetrical porphyrin arrays with conjugating and nonconjugating linker groups and the use of presenting scaffolds such as triptycenes. In order to circumvent a laborious and step-wise organic synthesis of porphyrin arrays efforts are underway to utilize principles of self-aggregation and organization for the construction of ordered nanostructural arrays on metal surfaces. Here, even rather simple systems are able to form highly ordered structures. On the other hand, thermal activation can be used to form covalent bonds between individual porphyrin molecules to yield highly ordered, large, and stable arrays. The type of structures formed depends on the porphyrinoid material, the metal surface, and the deposition methods.
Theoretical Study on The Adsorption of NO on Metal Macrocycles, Metal=Mn,Fe,Co,Ni,Cu,Zn
Authors: Nguyen Tien Quang , Padama Allan Abraham Bustria , Escano Mary Clare Sison , Kasai Hideaki
Published: April 2013

We have studied the electronic structure and the adsorption of nitric oxide (NO) on various metal phthalocyanines (MPc, M = Mn, Fe, Co, Ni, Cu, Zn). By fully optimized geometries and electronic structure of various MPcs, we found that the 3d states of metals mainly contributed to ground-state electronic structure near the Fermi level of MPc and, to some degree, the p states of carbon inner ring. Those contribution of 3d states decreases as we move across the periodic table from Mn to Zn following the increase of d orbital occupancies. We also found that NO strongly bonds to the centre metal with end-on configuration and results in an opening of HOMO-LUMO energy gap in case of MnPc, FePc, and CoPc. While it shows a physisorption with other MPcs (Ni, Cu, and Zn) and results in an appearance of molecular electronic states at HOMO-LUMO gap.
Novel Core/Shell Ni@NiO/Pt as High Efficient Electrocatalyst for Alkaline Direct Ethanol Fuel Cells
Authors: Hasan Maksudul , Newcomb Simon B , Razeeb Kafil M.
Published: April 2013

A one-dimensional core/shell hybrid electrocatalyst for alkaline direct ethanol fuel cells (ADEFC) has been fabricated using Ni@NiO nanowire arrays (NWA) as a novel support for porous Pt nanoparticles (Pt NP). The Ni@NiO NWA has been fabricated by direct electrodeposition inside a polycarbonate template and the subsequent conversion of the outer shell of Ni into an oxide by oxygen plasma annealing. The Pt NP have been deposited onto the Ni@NiO NWA surface by the borohydride technique. Transmission electron microscopy (TEM) has shown that the PtNP contain a homogeneous distribution of fine pores. The electro-catalytic activity for the electro-oxidation of ethanol in alkaline media for Ni@NiO NWA/Pt has been found to be 126 mA/cm2. Chronoamperometry has been used to show that the Ni@NiO NWA/Pt electrocatalyst exhibits favorable stability and activity as well as tolerance to CO-like poisoning during ethanol electro-oxidation at temperatures of 21{degree sign}C and 50 {degree sign}C. The Ni@NiO NWA/Pt electrocatalyst is a potential candidate to replace the commercial Pt/C NP anode electrocatalysts currently used in ADEFC.
Photoelectrooxidation of Water on Hematite Thin Films
Authors: Herrmann-Geppert Iris , Bogdanoff Peter , Fengler Steffen , Dittrich Thomas , Fiechter S.
Published: April 2013

Hematite photoanodes for the oxygen evolution reaction (OER) were prepared by a cost-efficient sol-gel procedure. We show that annealing and plasma post-treatments improve significantly the photoelectrochemical properties for the OER. Annealing steps lead to a reorganization of the crystal structure and thereby to a pronounced shift of the photocurrent to negative potentials. Surface photovoltage measurements (SPV) indicate an enhanced separation of charge carriers originated from the band gap photoabsorption. Nevertheless a more pronounced effect on the catalytic efficiency was gained by a surface-treatment in oxygen plasma. X-ray photoelectron spectroscopy (XPS) analysis reveals an oxygen enriched surface layer with new oxygen species which might be responsible for the improved electrochemical activity. SPV measurements identify an increased fraction of transferred charge carriers from this newly produced surface defects. The combination of these post-treatments leads finally to an efficient hematite photoanode for the OER.
Nanostructured Hybrid Electrocatalytic Materials for Ethanol Oxidation: Activation of Pt-Ru Centers through Modification with Selected Metal Oxides
Authors: Klak Karolona , Marks Diana , Wadas Anna , Piatek Monika , Lotowska Weronika , Zoladek Sylwia , Rutkowska Iwona A , Kulesza Pawel J.
Published: April 2013

Ethanol is a biofuel of potential importance to the technology of low-temperature polymer-membrane fuel cells. The alcohol can be ideally oxidized to carbon dioxide thus delivering 12 electrons. But realistically the reaction is rather slow and complex at ambient conditions. Obviously, there is a need to develop novel electrocatalytic materials. In the present work we have utilized as carriers (matrices) carbon nanotubes (CNTs) modified with nanostructured titanium dioxide. TiO2 can be considered as model robust transition metal oxide that, by analogy to tungsten oxide or zirconium oxide (also considered here), is capable of generating of interfacial reactive hydroxy groups on the surfaces. By dispersing bimetallic platinum-ruthenium catalytic nanocenters over the CNT-supported TiO2, the electrocatalytic activity of Pt-Ru nanoparticles towards oxidation of ethanol has been enhanced. Remarkable increases of electrocatalytic currents measured under voltammetric and chronoamperometric conditions have been observed. Electrochemical diagnostic experiments have been supported with microscopic monitoring of morphology using transmission electron microscopy (TEM). In addition to the presence of active interfacial hydroxyl groups, an important issue is the improvement of overall conductivity titanium dioxide - due to the presence of dispersed carbon nanotubes. Comparative measurements aimed at investigation of the presence of dispersed nanostructured metal oxides on dynamics of the oxidation of different fuels (here formic acid).
Development of Composite Non-Platinum IrFe (1:16)/C Nanoparticle as Novel Anodic Catalyst in PEMFC
Authors: Li Bing , Yang Daijun , Lin Rui , Yu Zhuoping , Ma Jianxin
Published: April 2013

The active, carbon-supported 10 wt.%Ir-40wt.%Fe (1:16, atomic ratio) nanoparticle catalyst was successfully synthesized by an EG reduction method as novel, suitable anode electrode materials for PEMFCs applications. IrFe nanoparticles showed a narrow particle size distribution centered around 1.5-2 nm, and were uniformly dispersed on Vulcan XC-72 supports. In-situ cyclic voltammetry technique (CV) was used to characterize the performance of PEMFC as anode catalyst. It was found that the 10%Ir-40%Fe/C catalyst affects the performance of electrocatalyst significantly based on the discharge characteristics of the fuel cell. High cell performance of a membrane electrode assembly (MEA) on the anode was achieved with a loading of 0.1 mg cm-2 10%Ir-40%Fe/C catalyst, which results in a maximum a power density of 889.6 mW cm-2. This value is 32% higher performance than that for commercially available Pt/C catalyst. It strongly suggested that the novel IrFe/C catalyst proposed in this work could be promising for PEMFC.
Sulfonic Acid Bisphenol A Membranes for Fuel Cell Applications
Authors: Blanco Lyzed T. , Loureiro Felipe Augusto Moro , Pacheco Pereira Robson , Rocco Ana Maria
Published: April 2013

In the present work, sulfonated (IPN-SO3H) membranes were obtained from PEI/DGEBA interpenetrating polymer network membranes and characterized by vibrational infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and electrochemical impedance spectroscopy (EIS). The membranes exhibited thermal stability higher than 230 oC and conductivity of about 10-3 Ω-1cm-1 at 80 oC, with activation energy values indicating different proton conduction mechanisms depending on the sulfonation degree. Due to the overall properties of the IPN-SO3H membranes, they can be considered promising materials for application in PEMFC.
Nafion β-Relaxation Dependence on Temperature and Relative Humidity Studied by Dielectric Spectroscopy
Authors: Matos Bruno Ribeiro de , André Dresch Mauro , Inácio Santiago Elisabete , Linardi Marcelo , Zanetti de Florio Daniel , Coral Fonseca Fabio
Published: April 2013

Nafion β-relaxation was studied by detailed dielectric spectroscopy measurements carried out over a wide range of both temperature and relative humidity. Both cast and extruded Nafion were compared in the H+, Na+, and Cs+ forms to evaluate contributions arising from membrane morphology and ionic interactions. The combined data indicated that β-relaxation is related to the motion of the polymer side chains. The shift to lower frequencies of the β-relaxation was shown to be more pronounced for samples containing high water content at temperatures above the α-relaxation, evidencing that the electrostatic repulsions between bare sulfonic groups reduce the side chain mobility. An abrupt change of relaxation time was observed at relative humidity > 60% and associated with a change of morphology of the ionomer from an inverted micellar structure to a rodlike network.
Low Cost Hydrogen Fuel Cell
Authors: Dara Mohammad Saad , Lam Alfred , Fatih Khalid , Wilkinson David P.
Published: April 2013

In this paper a hydrogen fuel cell is operated in the absence of a membrane at 60°C. The fuel cell was fed a non-humidified hydrogen fuel and a 2 M Fe(ClO4)3, 0.22M Fe(ClO4)2, and 0.2 M HClO4 oxidant catholyte. A 3-D carbon cathode in conjunction with a 0.5 M HClO4 liquid electrolyte was used to eliminate the membrane. Non-optimized maximum power density upwards of 220 mW/cm² was achieved with a total Pt content of the fuel cell as low as 0.05 mg/cm². Elimination of the PEM and reduction in total fuel cell Pt-catalyst content are expected to offer significant cost savings over conventional fuel cell technology.
The Oxygen Evolution Reaction at Hydrous Iron Oxide Films in Base: Kinetics and Mechanism
Authors: Doyle Richard L. , Lyons Michael E.G.
Published: April 2013

The oxygen evolution reaction at multi-cycled iron oxy-hydroxide films in aqueous alkaline solution is discussed. Steady-state Tafel plot analysis and electrochemical impedance spectroscopy have been used to elucidate the kinetics and mechanism of oxygen evolution. Tafel slopes of ca. 60 mV dec−1 and ca. 120 mV dec−1 are found at low and high overpotentials, respectively, with the former reducing to 40 mV dec−1 for very thick films. A reaction order of ca. 1.0 is observed irrespective of overpotential and film thickness. A mechanistic scheme involving the active participation of octahedrally coordinated anionic iron oxyhydroxide surfaquo complexes, which form the porous hydrous layer, is proposed. The latter structure contains considerable quantities of water molecules which facilitate hydroxide ion discharge at the metal site during active oxygen evolution.
High Temporal Resolution Bio-Sensing Using Nitrogen-Incorporated Nanodiamond Ultra-Microelectrode Array by Fast Scan Cyclic Voltammetry
Authors: Raina Supil , Kang Weng Poo , Davidson Jim L. , Huang Jin Hua
Published: April 2013

Microelectrodes have several benefits over macroelectrodes by virtue of their size. Their advantages include lower capacitance and uncompensated resistance loss, enhanced temporal and spatial resolution, usability in highly resistive media, increased signal to noise ratio. An array of microelectrodes can deliver these benefits along with signal amplification. Neurotransmitters, such as dopamine, undergo rapid fluctuations in concentrations occurring at a sub-second time scale. Real-time monitoring and measurement of these concentration changes, in-vivo or in-vitro, requires the use of ultra-microelectrode arrays (UMEAs). A nitrogen incorporated nanodiamond UMEA was fabricated using silicon microfabrication technology and microwave PECVD process. The array of 2500 UMEs, projects above the SiO2 insulating matrix, thus providing a 3-dimensional surface. Fast scan cyclic voltammetry at 300V/s was used to examine the temporal response and sensitivity for dopamine detection. A large negative holding potential was employed to promote DA pre-concentration in between the voltage scans.
Development of Acetylcholinesterase Biosensor for the Detection of Organophosphates
Authors: Cho Esther , Crumbley Jessica , Suroviec Alice H
Published: April 2013

A biosensor using acetylcholinesterase immobilized onto gold microelectrodes for the detection of organophosphates compounds was developed. The degree of inhibition of the acetylcholinesterase by the organophosphates was determined by measuring the oxidation current of the thiocholine produced by the AChE catalyzed hydrolysis of acetylthiocholine. The biosensor detected methyl-parathion concentrations as low as 5 micromolar with good precision, reproducibility and stability. Actual water samples were also tested and showed the feasibility of using these biosensors for field-testing of organophosphate compounds.
Finite-Element Computer Simulations on Cyclic Voltammograms Measured at Recessed Nanodisk-Array Electrodes
Authors: Tran Ba Khanh Hoa , Ito Takashi
Published: April 2013

The characteristics of cyclic voltammograms (CVs) at recessed nanodisk-array electrodes (RNEs) were investigated using finite-element computer simulations. Simulations were performed for RNEs based on planar electrodes coated with electrically-insulating films comprising hexagonally-distributed, vertically-oriented cylindrical nanopores (12 nm in radius, 30 nm deep). CVs and concentration profiles of redox species were simulated by varying electrode spacing (2s) and the diffusion coefficient of a redox species within the nanopores (Dpore). For nm-scale s and large Dpore, peak-shaped CVs with currents very similar to those at a film-free electrode were obtained due to the overlapping of diffusion layers extended from multiple electrodes. However, larger s and smaller Dpore gave smaller peak currents, as the nanoscale electrodes limited the number of redox species to be reacted. Further increase in s offered sigmoidal CVs though s was small enough for the overlapping of diffusion layers. These trends were consistent with experimental CVs measured at RNEs.
Study of Low Temperature (180 oC) Dual-Select-Diode for Applications to Pixel Switching Devices for Flexible Displays
Authors: Kang Sin-Young , Keum Ki-Su , Park Jung Hoon , Song Tae-Ho , Hong Wan-Shick
Published: April 2013

Thin film dual select diodes (TF-DSDs) were fabricated at a low temperature (180 oC) for applications to pixel switching devices for flexible displays. The Silicon-rich silicon nitride (SRSN) films were prepared by catalytic chemical vapor deposition (Cat-CVD) technique. Composition of the source gas mixture affected directly the photoluminescence spectra and the current-voltage characteristics of the SRSN films. We observed non-linear, asymmetric current-voltage characteristics that can be tuned by controlling the film deposition parameters.
Structural, Morphological and Optical Properties of Copper Oxide Nano Particles
Authors: Dhanasekaran Vickraman , Mahalingam Thaiyan , Chandramohan Rathinam
Published: April 2013

CuO nano-particles were successfully prepared via sol-gel method. The prepared powder was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS) and UV-Vis-NIR spectroscopy. Structural studies revealed that the CuO nano-particles were polycrystalline in nature with monoclinic structure. The crystallite size of the CuO nano-particle is estimated to be ~10 nm. The microstrain, number of crystallites per unit area and dislocation density of the nano particles was calculated. The rod shaped nano grains were observed using SEM and TEM studies. The optical optical band gap was estimated and reported.
Spectroscopic Study of Vanadium Electrolytes in Vanadium Redox Flow Battery (VRFB)
Authors: Gao Xin , Lynch Robert Patrick , Leahy Martin J, , Buckley Denis Noel
Published: April 2013

In this paper, we characterize the absorbance spectra and explain the spectroscopic behavior typically found in VRFB electrolytes at various mixture ratios of VII/VIII and VIV/VV mixtures in H2SO4. We demonstrate that the linear behavior of absorbance with respect to mixture ratio for the anolyte (VII/VIII) can be used to determine mixture ratio. In addition, we find that the non-linear behavior of the absorbance with respect to mixture ratio for the catholyte (VIV/VV) is due to the formation of a vanadium complex.
Acute volume expansion attenuates hyperthermia-induced reductions in cerebral perfusion during simulated hemorrhage
Authors: Schlader Zachary J. , Seifert Thomas , Wilson Thad E. , Bundgaard-Nielsen Morten , Secher Niels H. , Crandall Craig G.
Published: April 2013

Hyperthermia reduces the capacity to withstand a simulated hemorrhagic challenge, but volume loading preserves this capacity. This study tested the hypotheses that acute volume expansion during hyperthermia increases cerebral perfusion and attenuates reductions in cerebral perfusion during a simulated hemorrhagic challenge induced by lower-body negative pressure (LBNP). Eight healthy young male subjects underwent a supine baseline period (pre-LBNP), followed by 15- and 30-mmHg LBNP while normothermic, hyperthermic (increased pulmonary artery blood temperature ∼1.1°C), and following acute volume infusion while hyperthermic. Primary dependent variables were mean middle cerebral artery blood velocity (MCAvmean), serving as an index of cerebral perfusion; mean arterial pressure (MAP); and cardiac output (thermodilution). During baseline, hyperthermia reduced MCAvmean ( P = 0.001) by 12 ± 9% relative to normothermia. Volume infusion while hyperthermic increased cardiac output by 2.8 ± 1.4 l/min ( P < 0.001), but did not alter MCAvmean ( P = 0.99) or MAP ( P = 0.39) compared with hyperthermia alone. Relative to hyperthermia, at 30-mmHg LBNP acute volume infusion attenuated reductions ( P < 0.001) in cardiac output (by 2.5 ± 0.9 l/min; P < 0.001), MAP (by 5 ± 6 mmHg; P = 0.004), and MCAvmean (by 12 ± 13%; P = 0.002). These data indicate that acute volume expansion does not reverse hyperthermia-induced reductions in cerebral perfusion pre-LBNP, but that it does attenuate reductions in cerebral perfusion during simulated hemorrhage in hyperthermic humans.
Mechanisms of causal interaction between short-term RR interval and systolic arterial pressure oscillations during orthostatic challenge
Authors: Faes Luca , Nollo Giandomenico , Porta Alberto
Published: April 2013

The transition from the supine to the upright position requires a reorganization of the mechanisms of cardiovascular control that, if not properly accomplished, may lead to neurally mediated syncope. We investigated how the patterns of causality between systolic arterial pressure (SAP) and cardiac RR interval were modified by prolonged head-up tilt using a novel nonlinear approach based on corrected conditional entropy (CCE) compared with the standard approach exploiting the cross-correlation function (CCF). Measures of coupling strength and delay of the causal interactions from SAP to RR and from RR to SAP were obtained in 10 patients with recurrent, neurally mediated syncope (RNMS) and 10 healthy control (CO) subjects in the resting supine position ( su) and after head-up tilting during early ( et; ∼2 min) and late ( lt; ∼15 min or before presyncope) epochs of upright posture. Main results were that 1) the coupling strength from SAP to RR increased significantly from su to et in both groups; by contrast, upon lt, the coupling strength was kept high in CO subjects and dropped to low values in RNMS patients; 2) in RNMS patients, the delay from SAP to RR was higher than in healthy controls and increased moving from et to lt. Although these trends were evident using the CCE approach, statistical significance was not attained using the CCF approach. These results indicate the necessity of dissecting causality between RR and SAP to properly assess directional mechanisms from the closed-loop cardiovascular regulation and suggest a weakened and slowed baroreflex as a major mechanism involved in the cardiovascular impairment associated to neurally mediated syncope.
Mechanisms of Mid-Holocene Precipitation Change in the South Pacific Convergence Zone
Authors: Mantsis Damianos F. , Lintner Benjamin R. , Broccoli Anthony J. , Khodri Myriam
Published: April 2013

The variability of the South Pacific convergence zone (SPCZ) during the mid-Holocene is investigated using models archived in the Paleoclimate Modelling Intercomparison Project Phase II (PMIP2) database. Relative to preindustrial conditions, mid-Holocene top-of-atmosphere insolation was relatively lower during austral summer [December–February (DJF)], which is the season when the SPCZ is at its peak intensity. In response to this perturbation, the PMIP2 models simulate a displacement of the SPCZ to the southwest. This SPCZ shift is associated with a sea surface temperature (SST) dipole, with increased rainfall collocated with warm SST anomalies. Decomposing the DJF precipitation changes in terms of a diagnostic moisture budget indicates that the SPCZ shift is balanced to leading order by a change in the mean moisture convergence. Changes to the broad area of upper-level negative zonal stretching deformation, where transient eddies can become trapped and subsequently generate deep convection, support the notion that the SPCZ shift in the subtropics is tied to eddy forcing. Idealized experiments performed with an intermediate-level complexity model, the Quasi-Equilibrium Tropical Circulation Model (QTCM), suggest that the mid-Holocene change in rainfall in the SPCZ region as well as the equatorial Pacific is dominated by a change in the underlying SST. The tropical portion of the SPCZ is further remotely affected by the orbitally induced weakening of the Australian monsoon, even though this effect is weaker compared to the effect from SSTs.