bluuebunny/crossref_metadata_2025 huggingface dataset:
An uncountable family of copies of a non-chainable tree-like continuum in the plane
Authors: Hoehn L.
Published: March 2013

A well-known theorem of R. L. Moore states that the plane does not contain an uncountable family of pairwise disjoint triods. In 1974, Ingram demonstrated that the same is not true for non-chainable tree-like continua. The continua in Ingram’s family are not pairwise homeomorphic, making the example less applicable to the study of homogeneous continua in the plane. In this paper, we construct a non-chainable tree-like continuum

X
X

such that the product of

X
X

with the Cantor set can be embedded in the plane.
Making Books for Mr Murray: The Case of Edward Parry's Third Arctic Narrative
Authors: Cavell Janice
Published: March 2013

The Arctic explorer Edward Parry was among the most admired heroes of the 1820s, and his four narratives, all published by John Murray, won exceptionally high praise from reviewers. However, the praise was not unmixed with criticism. This article examines the reception of the third narrative, which was the least favourably received of the four. Reviewers' praise of it was often combined with insinuations that the true aim of the Admiralty expeditions led by Parry and his fellow naval officers was the production of luxurious and profitable quartos (or, as it was then termed, ‘book-making’). Many of the reviews demonstrate a sceptical and highly sophisticated approach to exploration literature as a genre. The case of Parry's third narrative therefore demonstrates the complexity of the processes through which the credibility and cultural authority of exploration narratives were negotiated.
Printers' Flowers as Evidence in the Identification of Unknown Printers: Two Examples From 1715
Authors: Wilkinson Hazel
Published: March 2013

This paper identifies John Darby of Bartholomew Close as the printer of the 1715 Tonson edition of the Works of Edmund Spenser, and the third edition of Edward Young's A Poem on the Last Day. The identifications are based on the evidence of printers' flowers. It is shown that composed arrangements of printers' flowers were sometimes kept as standing type and used in the printing of multiple works; the fact that this can allow unknown printers to be identified is explained and demonstrated for the first time. The collation of arrangements of printers' flowers, it is suggested, could be used more extensively in the future to gain a fuller picture of John Darby's career, and could potentially be applied to the works of other printers.
Exact and explicit expression of the atomic pair distribution function as obtained from X-ray total scattering experiments
Authors: Masson Olivier , Thomas Philippe
Published: March 2013

The atomic pair distribution function (PDF) as obtained from X-ray or neutron total scattering experiments has proved to be powerful in obtaining valuable structural information for many complex functional materials, be they amorphous or crystalline. In the case of measurements made with X-rays and for samples containing more than one kind of atom, the usefulness of the PDF is, however, somewhat hampered because of the lack of an exact and simple expression relating it to the structure of the materials. Only an approximate relationship exits, which is still in use today. This is particularly detrimental given the wide availability of X-ray sources and the increasing quality of PDFs obtained with laboratory sources. In this paper, the exact and explicit expression of the PDF as obtained from X-ray scattering is derived with respect to partial functions. This expression allows exact and efficient calculation of the PDF from any structure model without using approximate formulae.
Detection of alternative conformations:Shift_plotandAC_predictionprograms
Authors: Sobolev Oleg V.
Published: March 2013

Increased mobility of poorly ordered atoms compared to well ordered ones in unrestrained refinement was adopted as the basis for the development of a method for predicting alternative conformations. Two programs for the analysis of atomic mobility are presented.Shift_plotmay be useful for visual analysis of magnitudes of atomic shifts in refinement.AC_predictionimplements automatic decision-making procedures based on atomic shift magnitudes in unrestrained refinement to highlight the specific residues that are likely to harbour alternative conformations and that hence require checkingviaelectron density maps.
Bayesian reconstruction ofP(r) directly from two-dimensional detector imagesviaa Markov chain Monte Carlo method
Authors: Paul Sudeshna , Friedman Alan M. , Bailey-Kellogg Chris , Craig Bruce A.
Published: March 2013

The interatomic distance distribution,P(r), is a valuable tool for evaluating the structure of a molecule in solution and represents the maximum structural information that can be derived from solution scattering data without further assumptions. Most current instrumentation for scattering experiments (typically CCD detectors) generates a finely pixelated two-dimensional image. In continuation of the standard practice with earlier one-dimensional detectors, these images are typically reduced to a one-dimensional profile of scattering intensities,I(q), by circular averaging of the two-dimensional image. Indirect Fourier transformation methods are then used to reconstructP(r) fromI(q). Substantial advantages in data analysis, however, could be achieved by directly estimating theP(r) curve from the two-dimensional images. This article describes a Bayesian framework, using a Markov chain Monte Carlo method, for estimating the parameters of the indirect transform, and thusP(r), directly from the two-dimensional images. Using simulated detector images, it is demonstrated that this method yieldsP(r) curves nearly identical to the referenceP(r). Furthermore, an approach for evaluating spatially correlated errors (such as those that arise from a detector point spread function) is evaluated. Accounting for these errors further improves the precision of theP(r) estimation. Experimental scattering data, where no ground truth referenceP(r) is available, are used to demonstrate that this method yields a scattering and detector model that more closely reflects the two-dimensional data, as judged by smaller residuals in cross-validation, thanP(r) obtained by indirect transformation of a one-dimensional profile. Finally, the method allows concurrent estimation of the beam center andDmax, the longest interatomic distance inP(r), as part of the Bayesian Markov chain Monte Carlo method, reducing experimental effort and providing a well defined protocol for these parameters while also allowing estimation of the covariance among all parameters. This method provides parameter estimates of greater precision from the experimental data. The observed improvement in precision for the traditionally problematicDmaxis particularly noticeable.
P–V–Tequation of state of synthetic mirabilite (Na2SO4·10D2O) determined by powder neutron diffraction
Authors: Fortes A. D. , Brand H. E. A. , Vočadlo L. , Lindsay-Scott A. , Fernandez-Alonso F. , Wood I. G.
Published: March 2013

Neutron powder diffraction data have been collected from Na2SO4·10D2O (the deuterated analogue of mirabilite), a highly hydrated sulfate salt that is thought to be a candidate rock-forming mineral in some icy satellites of the outer solar system. These measurements, made using the OSIRIS instrument on the ISIS neutron spallation source, covered the range 0.1 <P< 545 MPa and 150 <T< 270 K. The refined unit-cell volumes as a function of pressure and temperature are parameterized in the form of a Birch–Murnaghan third-order equation of state, and the anisotropic linear incompressibilities are represented in terms of the elastic strain tensor. At 270 K, the bulk modulusK0,270= 19.6 (1) GPa, its first pressure derivative ∂K/∂P= 5.8 (5) and its temperature dependence ∂K/∂T = −0.0175 (6) GPa K−1. The stiffest direction at 270 K, with a linear bulk modulus of ∼82 GPa, is coincident with the twofold axis of this monoclinic crystal. Of the remaining two principal directions, the most compressible (K≃ 44 GPa) is roughly aligned with thecaxis, and the intermediate value (K≃ 59 GPa) is therefore approximately collinear witha*. With the aid of additional published data, a number of other important thermodynamic quantities have been derived, including the Grüneisen and Anderson–Grüneisen parameters, and the volume and enthalpy of melting along the high-pressure melting curve. Additional data obtained during this work, concerning the elastic properties of deuterated ice IV, are also presented.
RAMM: a new random-model-based method for solvingab initiocrystal structure using theEXPOpackage
Authors: Altomare Angela , Cuocci Corrado , Moliterni Anna , Rizzi Rosanna
Published: March 2013

The new method RAMM (random-model-based method) has been developed and implemented in theEXPOcomputing program for improving theab initiocrystal structure solution process. When the available information consists of only the experimental powder diffraction pattern and the chemical formula of the compound under study, the classical structure solution approach follows two main steps: (1) phasing by direct methods (or by Patterson methods) in order to obtain a structure model (this last is usually incomplete and/or approximate); (2) improving the model by structure optimization techniques. This article proposes the alternative procedure RAMM, which skips step (1) and supplies a fully random model to step (2). This model is then submitted to effective structure optimization tools present inEXPO– wLSQ (weighted least squares), RBM (resolution bias minimization) and COVMAP (a procedure of electron density modification based on the concept of covariance between points of the map) – which are able to lead to the correct structure. RAMM is based on a cyclic process, generating several random models which are then optimized. The process stops automatically when it recognizes the correct structure.
Synthesis and characterisation of new modified anti‐corrosive polyesteramide resins by partial replacement of the ingredient source of the polybasic acid for organic surface coatings
Authors: Abd El‐Wahab H. , Abd El‐Hai F. , Naser A.M. , El‐Bialy Z.I. , Mostafa M. , Lin L.
Published: March 2013

Purpose

Polymeric systems based on polyesteramides (PEA) are high performance materials, which combine the useful properties of polyester and polyamide resins, and find many applications, most importantly as protective surface coatings. The purpose of this paper is to characterise and evaluate new modified anti‐corrosive PEA resins for use in protective coating formulations.

Design/methodology/approach

In the study report here, new modified PEA compositions were prepared and evaluated as vehicles for surface coating. The PEA resins were obtained by means of a condensation polymerisation reaction between phthalic anhydride (PA) and N,N‐bis‐(2‐hydroxyethyl) linseed oil fatty acid amide (HELA) as the ingredient source of the polyol used. The phthalic anhydride was partially replaced with N‐phthaloylglutamic acid NPGA as the ingredient source of the dibasic acid. The structure of the resin was confirmed by FT‐IR spectral studies. Coatings of 50±5 μm thickness were applied to the surface of glass panels and mild steel strips by means of a brush. The coating performance of the resins was evaluated using international standard test methods and involved the measurement of phyisco‐mechanical properties and chemical resistance.

Findings

The tests carried out revealed that the modified PEA based on N‐phthaloylglutamic acid (NPGA) enhanced both phyisco‐mechanical and chemical properties. Also, the resins were incorporated within primer formulations and evaluated as anti‐corrosive single coatings. The results illustrate that the introduction of N‐phthaloylglutamic acid, within the resin structure, improved the film performance and enhances the corrosion resistance performance of PEA resins.

Practical implications

The modified PEA compounds can be used as binder in paint formulations to improve chemical, physical and corrosion resistance properties.

Originality/value

Modified PEA resins are cheaper and can be used to replace other more expensive binders. These modified PEA resins can compensate successfully for the presence of many the anticorrosive paint formulations and thus lower the costs. The main advantage of these binders is that they combine the properties of both polyester and polyamide resins based on nitrogenous compound, are of lower cost, and they also overcome the disadvantages of both its counterparts. Also, they can be applied in other industrial applications.
Eco‐friendly tannin‐phenol formaldehyde resin for producing wood composites
Authors: Jahanshaei S. , Tabarsa T. , Asghari J.
Published: March 2013

Purpose

The purpose of this paper is to describe the development of an eco‐friendly tannin‐phenol formaldehyde resin (PFT) applicable in the wood composite industry.

Design/methodology/approach

The bark of oak (Quercus castaneifolia) contains a large amount of condensed tannin. Condensed tannin, with a large amount of Catechol groups was considered for reducing the formaldehyde emission level on the adhesive system. Physical characteristics of synthesized PFT resin were evaluated.

Findings

For optimal extraction, three solvents were used in the extraction process. The results showed that a mixture of water‐methanol (1:1 v/v) as extracting solvent is the best solvent and yields about 14 per cent tannin based on dry weight of bark. For producing tannin phenol formaldehyde adhesive, 10 per cent, 20 per cent and 30 per cent (based on PF dry weight) of PF, substituted with natural extracted tannin. For evaluating PFT performance effects of percentage amount of substitution tannin content on the gel time, viscosity, pH, and density of adhesives were evaluated. Based on emission test (JIS A 1460‐2001) formaldehyde emission of PFT 10 per cent, 20 per cent and 30 per cent were 1.13, 1.12 and 0.4 mg/100 g, which is very low compared with tannin‐free PF.

Research limitations/implications

Tannin‐PF adhesive compared to PF adhesive had lower PH, higher viscosity and shorter gel time.

Practical implications

The method developed provides a simple and excellent renewable resource “tannin” which can be used or partially substituted in phenol formaldehyde adhesive.

Originality/value

Results showed that replacing PF for tannin reduces modulus of rupture (MOR) and modulus of elasticity (MOE) slightly but has significant effects on IB, water absorption and thickness swelling.
Bagasse hydrogels: water absorption and ions uptake
Authors: Ahmed A.E.‐S.I. , El‐Masry A.M. , Saleh A. , Nada A.
Published: March 2013

Purpose

The purpose of this paper is to prepare and optimize the preparation conditions of some new hydrogels and in addition, evaluate their water absorbance at different mediums and their ability to remove ions from aqueous solutions.

Design/methodology/approach

Cellulose was extracted from depithed bagasse at two different pulping conditions; 3 and 6 hours cooking times, pulp (I) and (II), respectively. These pulps, in addition to cotton linter for comparison, were grafted with acrylamide followed by cross‐linking with glutaraldehyde. The networks were partially hydrolyzed and the structures of products (before and after hydrolysis) were studied using FTIR, SEM, TGA and X‐ray. The optimum preparation conditions were identified, before and after hydrolysis, to achieve maximum absorbance and the ability of prepared hydrogels to remove ions from solutions was investigated.

Findings

Maximum level of absorption was recorded using hydrogels prepared with monomer concentration =0.8 mol/l, cross‐linker concentration =0.01 mol/l, reaction time =2 hours and temperature =65°C. Hydrogels prepared using pulp (I) showed the best absorbance behavior and a tendency to remove ions from water.

Research limitations/implications

The ability of the prepared gels to remove ions from water could be further investigated to evaluate the ability of their use in a multi‐filtration system for water treatment.

Practical implications

This piece of work has suggested a simple way to convert an agricultural waste to hydrogel able to remove metal ions from water.

Social implications

Consuming this type of waste reduces the risks resulting from its burning in some countries, such as Egypt, that produce large amounts of it.

Originality/value

In this paper, low cost hydrogels, with expected value in water treatment, were prepared using agricultural wastes. They have shown better reactivity than gels prepared using pure cellulosic materials (cotton linter).
Solidification and reliability of lead‐free solder interconnection
Authors: Yu Hao , Shangguan Dongkai
Published: March 2013

Purpose

As a literature review article, the purpose of this paper is to highlight the intricate interaction and correlation between the interconnection microstructure and the failure mechanism. It is therefore critical to summarize all the challenges in understanding solder solidification of interconnections.

Design/methodology/approach

Literature review.

Findings

Solidification of solder interconnections is therefore critical because it is the process during which the solder interconnection is formed. The as‐solidified microstructure serves as the starting point for all failure modes. Because of the miniaturization of electronics, the interconnection size decreases continuously, already to such a range that solder solidification takes place remarkably differently from the bulk ingot, on which solidification studies have been focused for decades. There are many challenges in understanding the solidification of tiny solder interconnections, including the complex metallurgical system, dynamic solder composition, supercooling and actual solidification temperature, localized temperature field, diverse interfacial IMC formation, and so on, warranting further research investment on solder solidification.

Originality/value

This paper provides a critical overview of the concerns in solidification study for lead‐free solder interconnection. It is probably an article initiating more attention towards solidification topics.
The differential transform method and Padé approximants for a fractional population growth model
Authors: Suat Erturk Vedat , Yıldırım Ahmet , Momanic Shaher , Khan Yasir
Published: March 2013

Purpose

The purpose of this paper is to propose an approximate method for solving a fractional population growth model in a closed system. The fractional derivatives are described in the Caputo sense.

Design/methodology/approach

The approach is based on the differential transform method. The solutions of a fractional model equation are calculated in the form of convergent series with easily computable components.

Findings

The diagonal Padé approximants are effectively used in the analysis to capture the essential behavior of the solution.

Originality/value

Illustrative examples are included to demonstrate the validity and applicability of the technique.
Approximate analytical solution to time fractional nonlinear evolution equations
Authors: Abdou M.A. , Yildirim Ahmet
Published: March 2013

Purpose

The purpose of this paper is to develop a scheme to study numerical solution of time fractional nonlinear evolution equations under initial conditions by reduced differential transform method.

Design/methodology/approach

The paper considers two models of special interest in physics with fractional‐time derivative of order, namely, the time fractional mKdV equation and time fractional convection diffusion equation with nonlinear source term.

Findings

The numerical results demonstrate the significant features, efficiency and reliability of the proposed method and the effects of different values are shown graphically.

Originality/value

The paper shows that the results obtained from the fractional analysis appear to be general.
Mixed convection in an inclined channel with heated porous blocks
Authors: Guerroudj N. , Kahalerras H.
Published: March 2013

Purpose

The purpose of this paper is to study numerically the fluid flow and heat transfer in an inclined channel provided with heated porous blocks on its lower plate.

Design/methodology/approach

The Brinkman‐Forchheimer extended Darcy model with the Boussinesq approximation is adopted for the flow in the porous regions. The governing equations with the appropriate boundary conditions are solved by the control volume method. The effect of some pertinent parameters such as the buoyancy force intensity, the porous blocks shape and height, the porous medium permeability and the Reynolds number are analyzed for various inclination angles ranging from −90° to +90°.

Findings

The results reveal, essentially, that the inclination angle of the channel can alter substantially the fluid flow and heat transfer mechanisms, especially at high Richardson and Darcy numbers. In this case, the maximum and minimum global Nusselt numbers are reached for α=+90° and α=−90°, respectively.

Research limitations/implications

The results obtained in this work are valid for an inclined channel with porous blocks attached on the heated parts of the lower plate, whereas the upper wall is thermally insulated.

Practical implications

The results obtained in this worky can be used in the thermal control of electronic components. The use of porous blocks mounted on the heat sources will increase the rate of heat removal in order to maintain the electronic components at an acceptable operating temperature.

Originality/value

The paper provides an interesting method to improve the cooling of electronic devices by use of a porous medium.
Exploring the public parameter of police integrity
Authors: Meyer Michael E. , Steyn Jean , Gopal Nirmala
Published: March 2013

Purpose

The purpose of this paper is to explore the contribution of the public component of Klockars’ and Kutnjak‐Ivkovic's organizational theory of police integrity to the understanding of police integrity.

Design/methodology/approach

The study employs a modified survey derived from “The Measurement of Police Integrity,” instrument developed by Klockarset al.Participants are constituted by a convenience sample of first‐year social studies students at the University of KwaZulu‐Natal (n=186) and 160 South African Police Service (SAPS) non‐commissioned officers throughout Gauteng Province, Republic of South Africa.

Findings

Overall, the data present a mixed picture of integrity in the SAPS. The current study is certainly suggestive that the SAPS faces serious challenges to establishing and sustaining integrity and that based on either absolutist or normative criteria, the organization falls below desired levels of professional integrity. However, there are also indications that a significant proportion of officers will support efforts of the organization to establish and maintain professional standards of integrity.

Practical implications

The findings, focused on non‐commissioned officers, contribute to a growing body of research across all levels of the SAPS. In addition, the research compares results from a non‐police sample, helping to contextualize the concept of integrity as it exists within the SAPS. More immediate implications relate to the potential for the development of a broad‐based integrity plan for the SAPS as a whole.

Originality/value

Previous research employing police only samples has concluded that the SAPS is an integrity‐challenged organization. While the present study agrees that the SAPS faces significant integrity challenges, the use of a comparative non‐policing sample also suggests that the Service is having some success in establishing integrity standards, at least in regard to lower level violations of organizational ethical standards.
Chondroitinase injection improves keloid pathology by reorganizing the extracellular matrix with regenerated elastic fibers
Authors: Ishiko Toshihiro , Naitoh Motoko , Kubota Hiroshi , Yamawaki Satoko , Ikeda Mika , Yoshikawa Katsuhiro , Fujita Hiroshi , Yamaguchi Hiroaki , Kurahashi Yasuhiro , Suzuki Shigehiko
Published: March 2013

Keloids are a proliferative fibrotic disease characterized by abnormal accumulation of extracellular matrix in the dermis. Keloid lesions lack skin plasticity due to deficiencies in elastic fiber formation in the extracellular matrix. The loss of elastic fiber is caused by excessive accumulation of chondroitin sulfate (CS), a sulfated glycosaminoglycan. However, there is no radical cure for keloids. Using a model system, we show herein that treatment of keloid tissues with chondroitinase ABC, an enzyme that specifically digests CS, improves clinical features of keloids. Keloid tissues obtained from patients were grafted on nude mice, and chondroitinase ABC was injected into the grafted keloid tissues. Chondroitinase ABC treatment significantly reduced the volume of keloid implants concomitant with recovery of elastic fiber formation. These results suggest that chondroitinase ABC injection is an effective therapy for keloid.
Top Management Team Members’ Decision Influence and Cooperative Behaviour: An Empirical Study in the Information Technology Industry
Authors: Buyl Tine , Boone Christophe , Hendriks Walter
Published: March 2013

Organizational leadership is generally distributed between the chief executive officer (CEO) and the top management team (TMT) members. Building on this observation, we present an empirical investigation of the cues for CEOs to delegate decision‐making influence to particular TMT members. In the literature, explanations both based on expertise and driven by similarity are described. In this study, we reconcile both explanations by examining the moderating role of the TMT's level of ‘cooperative behaviour’ (collaboration and information exchange). We analyse when and in what circumstances TMT members’ expertise and similarity to the CEO regarding his/her functional background and/or locus‐of‐control predict their decision‐making influence. We postulate that TMT cooperative behaviour will advance the effect of expertise on TMT members’ decision influence but impede the effect of similarity to the CEO. Our hypotheses are tested on a data set of 135 TMT members from 32 Dutch and Belgian information technology firms. Overall, we find that our proposed research model is confirmed for technology‐oriented decisions. Furthermore, we draw exploratory conclusions about the effect of TMT cooperative behaviour on the systematic distribution of decision influence in TMTs.
Characteristics of Forensic Imaging Performance—An Analysis of Forensic Imaging Bottlenecks
Authors: Branigan Steven
Published: March 2013

Disk imaging involves copying all of the data from a source disk drive to a target. Typically, the target for the copy is another disk drive. Forensic processes developed years ago do not appear to be adequate for current storage technology. For example, with disk drive capacities now exceeding 1 Terabyte, a typical disk imaging can take over 8 hours at typical rates. With disk drive capacities increasing, forensic copying is expected to take even longer. Along with increase in disk capacity, the industry has also seen an increase in data transfer rates. In many cases, forensic imaging is taking longer than necessary. To identify the bottlenecks, an examination of different methods used to transfer data from a source disk was performed. Factors considered were differing disk access technologies. One finding is that the USB disk access technology (version 2.0 and earlier) is a significant bottleneck for data transfer rates, especially when the USB device is a write‐blocker. Other factors that contribute to the efficiency of a forensic copy are the file system used to write a forensic image and the data transfer size used when reading from a disk drive. Optimal parameters for performing a forensic acquisition from a disk drive are identified.
Topological Variability of Fingerprint Ridge Density in a Sub‐Saharan Population Sample for Application in Personal Identification
Authors: Gutiérrez‐Redomero Esperanza , Quirós Juan A. , Rivaldería Noemí , Alonso María C.
Published: March 2013

Variability in ridge density in a sub‐Saharan population sample was studied by counting ridges in three fingerprint areas (two distal regions, radial and ulnar, and one proximal region) on the epidermal surface of the distal phalanx. Study material was obtained from the fingerprint impressions of 100 male sub‐Saharan subjects aged between 18‐ and 48‐years old. The results were compared with those obtained from a Spanish population sample. Sub‐Saharan males presented lower ridge density than Spanish males in the distal regions (radial and ulnar) of all fingers, whereas differences in the proximal region were only observed on some fingers. Using the differences observed between these populations, the likelihood ratio for inferring membership of one of the populations from a fingerprint of unknown origin was calculated; therefore, a ridge density of 14 or less for both areas (ulnar and radial), support an origin sub‐Saharan versus Spanish population.
The Significance of Adrenal Hemorrhage: Undiagnosed Waterhouse‐Friderichsen Syndrome, A Case Series
Authors: Tormos Lee Marie , Schandl Cynthia A.
Published: March 2013

A retrospective series of five cases of nontraumatic gross adrenal hemorrhage were identified in 800 consecutive forensic autopsies. All patients were males, of different ethnicities and with ages ranging from 2 to 48 years. All patients had a clinical history and autopsy findings suggestive of sepsis. Pre‐ or postmortem microbiological cultures were variably positive for Pseudomonas aeruginosa, Streptococcus pneumoniae, Staphylococcus aureus, and methicillin‐resistant Staphylococcus aureus. The fifth case was positive for yeast and a coagulase negative staphylococcus; contamination of this culture medium cannot be excluded. No cases had a culture positive for Neisseria meningitidis. We find that the reviewed patients with grossly or microscopically identifiable adrenal hemorrhage were otherwise healthy individuals who died suddenly as a consequence of bacterial infection. In each case, signs and symptoms compatible with premortem adrenal insufficiency were reported; in no instance was the adrenal hemorrhage clinically identified.
Efficacy of ‘breath holding at ease’ during CT pulmonary angiography in the improvement of contrast enhancement in pulmonary arteries
Authors: Li YeYuan Jourena , Lau Kenneth K , Ardley Nicholas , Lau Theodore
Published: March 2013

Introduction

The aim of this study is to assess whether breath‐hold at ease by patients during the CT pulmonary angiography (CTPA) will improve contrast enhancement in pulmonary arteries.

Methods

Retrospective review was conducted on 51 consecutive CTPA studies undertaken in the traditional method of patients taking deep inspiration and breath‐hold immediately prior to scanning, and subsequently 75 consecutive CTPA studies with patients breathing‐holding at ease immediately prior to and during the scanning. Attenuation values in pulmonary arteries of different anatomical levels in both groups were measured in Hounsfield unit (HU). Results were compared between the two groups.

Results

The mean attenuation value in pulmonary arteries including pulmonary trunk, main and proximal pulmonary arteries calculated in HU in the ‘deep inspiration and breath‐hold’ group was 327 HU (95% confidence interval: 315 to 339 HU). The mean attenuation value in pulmonary arteries in the ‘breath hold at ease’ group was calculated to be 390 HU (95% confidence interval: 381 to 399 HU); that is, an overall 17.95% increase (P‐value < 0.0001) in attenuation value in this group.

Conclusions

By asking patients to breath‐hold at ease instead of taking deep inspiration and breath hold prior to CTPA scan can effectively improve contrast enhancement in pulmonary arteries, therefore producing a higher‐quality CT pulmonary angiography scan.
Conservative medical treatment of ovarian hyperstimulation syndrome: a single center series and cost analysis study
Authors: Casals Gemma , Fábregues Francisco , Pavesi Marco , Arroyo Vicente , Balasch Juan
Published: March 2013

Objective

To present the results of a large series of patients with ovarian hyperstimulation syndrome treated with a conservative medical approach and to compare the cost of this treatment with outpatient management with paracentesis according to published data.

Design

Retrospective case series and cost analysis study using a decision‐tree model.

Setting

University hospital.

Population

496 consecutive patients with ovarian hyperstimulation syndrome treated in our center from 1991 to 2010.

Methods

All patients were treated with a conservative medical approach: (a) conservative outpatient approach: bed rest and a low‐sodium diet or (b) hospitalized patients: bed rest, low‐sodium diet, 20% albumin (60 g/day) and furosemide (20 mg/8 h).

Main outcome measures

Percentage of admissions, length of hospital stay and readmissions. Total cost of each therapeutic approach.

Results

(a) Conservative outpatient approach (n = 377): all cases solved without admission. (b) Hospitalized patients with conservative medical treatment (n = 119): 2.8 days of mean hospital stay, no patient required paracentesis or admission to intensive care unit. Readmissions: Five patients (4.2%) resolved on restarting medical treatment. (c) Cost‐analysis comparison: Cost of the outpatient approach with paracentesis: US$980 (range US$519–3557). Cost of conservative medical treatment: US$570 (range US$232–1640).

Conclusions

Ovarian hyperstimulation syndrome can be safely managed with a conservative medical approach, which was not found to be more expensive than outpatient management with paracentesis.
The effects of increasing body mass index on heartburn severity, frequency and response to treatment with dexlansoprazole or lansoprazole
Authors: Peura D. A. , Pilmer B. , Hunt B. , Mody R. , Perez M. C.
Published: March 2013

Background

Higher body mass index (BMI) is a recognised risk factor for gastro‐oesophageal reflux disease (GERD). Data regarding the impact of BMI on proton pump inhibitor (PPI) therapy are conflicting.

Aim

To assess the impact of BMI on baseline heartburn symptom severity and frequency and response to PPI therapy in patients with non‐erosive GERD (NERD) or erosive oesophagitis (EO).

Methods

In post hoc analyses of phase 3 trial data, 621 NERD and 2692 EO patients were stratified by BMI (<25, 25 to <30 and ≥30 kg/m2). NERD patients received either dexlansoprazole MR 30 mg or placebo daily for 4 weeks. EO patients received either dexlansoprazole MR 60 mg or lansoprazole 30 mg for 8 weeks. Symptom frequency and severity were assessed at baseline and subsequently by daily diary.

Results

In both the NERD and EO cohorts, baseline heartburn severity increased with increasing BMI. The impact of PPI therapy on the reduction in heartburn symptom frequency and severity in both NERD and EO patients was similar across BMI categories. EO healing rates in patients treated with dexlansoprazole but not lansoprazole were higher in obese patients compared with those with a BMI <30 kg/m2. Differences between the PPIs were small.

Conclusions

The PPIs evaluated in this study reduced the frequency and severity of 24‐h heartburn regardless of baseline BMI. In addition, because patients with higher BMI have more severe symptoms at baseline, they may experience greater therapeutic gain with dexlansoprazole (NERD and erosive oesophagitis) and possibly lansoprazole (erosive oesophagitis) treatment.
Histological Predictors of Outcome in Ependymoma are Dependent on Anatomic Site Within the Central Nervous System
Authors: Raghunathan Aditya , Wani Khalida , Armstrong Terri S. , Vera‐Bolanos Elizabeth , Fouladi Maryam , Gilbertson Richard , Gajjar Amar , Goldman Stewart , Lehman Norman L. , Metellus Phillipe , Mikkelsen Tom , Necesito‐Reyes Mary Jo T. , Omuro Antonio , Packer Roger J. , Partap Sonia , Pollack Ian F. , Prados Michael D. , Robins H. Ian , Soffietti Riccardo , Wu Jing , Miller C. Ryan , Gilbert Mark R. , Aldape Kenneth D. ,   Collaborative Ependymoma Research Network
Published: March 2013

Ependymomas originate in posterior fossa (PF), supratentorial (ST) or spinal cord (SC) compartments. At present, grading schemes are applied independent of anatomic site. We performed detailed histological examination on 238 World Health Organization grade II and III ependymomas. Among PF ependymomas, the presence of hypercellular areas, necrosis, microvascular proliferation and elevated mitotic rate (all P < 0.01) were significantly associated with worse progression‐free survival (PFS), while extensive ependymal canal formation was not (P = 0.89). Similar to the PF tumors, microvascular proliferation (P = 0.01) and elevated mitotic rate (P = 0.03) were significantly associated with worse PFS in the ST tumors. However, in contrast to PF tumors, extensive ependymal canals (P = 0.03) were associated with worse clinical outcome in ST ependymomas, but hypercellularity (P = 0.57) and necrosis (P = 0.47) were not. On multivariate Cox regression, after adjusting for relevant clinical variables, individual histological factors and a composite histological score remained significant among ST and PF ependymoma. In contrast to both PF and ST ependymoma, histological features were not found to be associated with PFS in SC tumors. Taken together, the clinical relevance of specific histological features in ependymoma appears to be related to the anatomic site of origin and suggests that site‐specific grading criteria be considered in future classification systems.
Dampness and moulds in relation to respiratory and allergic symptoms in children: results from Phase Two of the International Study of Asthma and Allergies in Childhood (ISAAC Phase Two)
Authors: Weinmayr G. , Gehring U. , Genuneit J. , Büchele G. , Kleiner A. , Siebers R. , Wickens K. , Crane J. , Brunekreef B. , Strachan D. P. ,   The ISAAC Phase Two Study Group
Published: March 2013

Background

Many studies report that damp housing conditions are associated with respiratory symptoms. Less is known about mechanisms and possible effect modifiers. Studies of dampness in relation to allergic sensitization and eczema are scarce.

Objective

We study the influence of damp housing conditions world‐wide on symptoms and objective outcomes.

Methods

Cross‐sectional studies of 8–12‐year‐old children in 20 countries used standardized methodology from Phase Two of the International Study of Asthma and Allergies in Childhood (ISAAC). Symptoms of asthma, rhinitis and eczema, plus residential exposure to dampness and moulds, were ascertained by parental questionnaires (n = 46 051). Skin examination, skin prick tests (n = 26 967) and hypertonic saline bronchial challenge (n = 5713) were performed. In subsamples stratified by wheeze (n = 1175), dust was sampled and analysed for house dust mite (HDM) allergens and endotoxin.

Results

Current exposure to dampness was more common for wheezy children (pooled odds ratio 1.58, 95% CI 1.40–1.79) and was associated with greater symptom severity among wheezers, irrespective of atopy. A significant (P < 0.01) adverse effect of dampness was also seen for cough and phlegm, rhinitis and reported eczema, but not for examined eczema, nor bronchial hyperresponsiveness. HDM sensitization was more common in damp homes (OR 1.16, 1.03–1.32). HDM‐allergen levels were higher in damp homes and were positively associated with HDM‐sensitization, but not wheeze.

Conclusion

A consistent association of dampness with respiratory and other symptoms was found in both affluent and non‐affluent countries, among both atopic and non‐atopic children. HDM exposure and sensitization may contribute, but the link seems to be related principally to non‐atopic mechanisms.
Prenatal smoke exposure, DNA methylation, and childhood atopic dermatitis
Authors: Wang I.‐J. , Chen S.‐L. , Lu T.‐P. , Chuang E. Y. , Chen P.‐C.
Published: March 2013

Background

The biological mechanisms of how prenatal smoke exposure leading to atopic disorders remain to be addressed. Whether prenatal smoke exposure affects DNA methylation leading to atopic disorders is not clear.

Objective

As most children suffering from atopic dermatitis (AD) continue to develop asthma later in life, we explored whether prenatal smoke exposure induces cord blood DNA methylation.

Methods

Methylation differences associated with smoke exposure were screened by Illumina Infinium 27K methylation arrays for 14 children from the Taiwan birth panel study cohort initially. Information about development of atopic dermatitis (AD) and risk factors was collected. Cord blood cotinine levels were measured to represent prenatal smoke exposure. CpG loci that demonstrated a statistically significant difference in methylation were validated by methylation‐dependent fragment separation (MDFS). Differential methylation in three genes (TSLP, GSTT1, and CYB5R3) was identified through the screen.

Results

Among these, only thymic stromal lymphopoietin (TSLP) gene displayed significant difference in promoter methylation percentage after being validated by MDFS (p = 0.018). TSLP gene was further investigated in a larger sample of 150 children from the cohort who completed the follow‐up study. Methylation status of the TSLP 5′‐CpG island (CGI) was found to be significantly associated with prenatal smoke exposure (OR=3.17, 95% CI=1.63–6.19) and with AD (OR=2.32, 95% CI=1.06–5.11). The degree of TSLP 5′CGI methylation inversely correlated with TSLP protein expression levels (r = −0.45, P = 0.001).

Conclusions & Clinical Relevance

The effect of prenatal tobacco smoke exposure on the risk for AD may be mediated through DNA methylation.
An Eye‐Tracking Study of Exploitations of Spatial Constraints in Diagrammatic Reasoning
Authors: Shimojima Atsushi , Katagiri Yasuhiro
Published: March 2013

Semantic studies on diagrammatic notations (Barwise & Etchemendy, ; Shimojima, ; Stenning & Lemon, ) have revealed that the “non‐deductive,” “emergent,” or “perceptual” effects of diagrams (Chandrasekaran, Kurup, Banerjee, Josephson, & Winkler, ; Kulpa, ; Larkin & Simon, ; Lindsay, ) are all rooted in the exploitation of spatial constraints on graphical structures. Thus, theoretically, this process is a key factor in inference with diagrams, explaining the frequently observed reduction of inferential load. The purpose of this study was to examine the empirical basis for this theoretical suggestion, focusing on the reality of the constraint‐exploitation strategy in actual practices of diagrammatic reasoning. Eye movements were recorded while participants used simple position diagrams to solve three‐ or four‐term transitive inference problems. Our experiments revealed that the participants could exploit spatial constraints on graphical structures even when (a) they were not in the position of actually manipulating diagrams, (b) the semantic rule for the provided diagrams did not match their preferences, and (c) the constraint‐exploitation strategy invited a partly adverse effect. These findings indicate that the hypothesized process is in fact robust, with the potential to broadly account for the inferential advantage of diagrams.
The co‐development of economies and institutions
Authors: Che Dawei , Shen Ling
Published: March 2013

In this study, we model the Schumpeterian growth theory in a simple discrete‐time framework in which both economies and institutions need to be developed. Individuals need to borrow from an imperfect financial market to develop an economy. A government can adopt two potential strategies for improving the borrowing capacity of individuals and, as a result, enhancing economic performance: ‘the rule of law’ and ‘industrial policies’. We interpret market‐oriented reform in transition economies as a shift from ‘industrial policies’, exemplified at the extreme by the traditional planned economy, to ‘the rule of law’. The presented model shows that both strategies could be the best choice at different stages of development.
Species–area relationships and extinctions caused by habitat loss and fragmentation
Authors: Rybicki Joel , Hanski Ilkka
Published: March 2013

The species–area relationship (SAR) has been used to predict the numbers of species going extinct due to habitat loss, but other researchers have maintained thatSARs overestimate extinctions and instead one should use the endemics–area relationship (EAR) to predict extinctions. Here, we employ spatially explicit simulations of large numbers of species in spatially heterogeneous landscapes to investigateSARsand extinctions in a dynamic context. TheEARgives the number of species going extinct immediately after habitat loss, but typically many other species have unviable populations in the remaining habitat and go extinct soon afterwards. We conclude that theEARunderestimates extinctions due to habitat loss, the continentalSAR(with slope ~0.1 or somewhat less) gives a good approximation of short‐term extinctions, while the islandSARcalculated for discrete fragments of habitat (with slope ~0.25) predicts the long‐term extinctions. However, when the remaining area of land‐covering habitat such as forest is roughly less than 20% of the total landscape and the habitat is highly fragmented, all currentSARsunderestimate extinction rate. We show how the ‘fragmentation effect’ can be incorporated into a predictiveSARmodel. When the remaining habitat is highly fragmented, an effective way to combat the fragmentation effect is to aggregate habitat fragments into clusters rather than to place them randomly across the landscape.
Parasite consumption and host interference can inhibit disease spread in dense populations
Authors: Civitello David J. , Pearsall Susan , Duffy Meghan A. , Hall Spencer R.
Published: March 2013

Disease dynamics hinge on parasite transmission among hosts. However, canonical models for transmission often fit data poorly, limiting predictive ability. One solution involves building mechanistic yet general links between host behaviour and disease spread. To illustrate, we focus on the exposure component of transmission for hosts that consume their parasites, combining experiments, models and field data. Models of transmission that incorporate parasite consumption and foraging interference among hosts vastly outperformed alternatives when fit to experimental data using a zooplankton host (Daphnia dentifera) that consumes spores of a fungus (Metschnikowia bicuspidata). Once plugged into a fully dynamic model, both mechanisms inhibited epidemics overall. Foraging interference further depressed parasite invasion and prevalence at high host density, creating unimodal (hump‐shaped) relationships between host density and these indices. These novel results qualitatively matched a unimodal density–prevalence relationship in natural epidemics. Ultimately, a mechanistic approach to transmission can reveal new insights into disease outbreaks.