bluuebunny/crossref_metadata_2025 huggingface dataset:
Solidification/stabilisation of Zn2+ ions in metakaolin and homra-blended cement matrices
Authors: Amin Mohamed S. , Hashem Fayza S. , Mohamed Maha R.
Published: August 2012

Ordinary type I Portland cement (OPC) and blended OPC with 30 wt% metakaolin and/or homra (crushed clay bricks) were used for stabilisation/solidification of zinc (Zn2+) ions. Contents of Zn2+ ions representing 0·5 and 1·0 wt% of the solid binder were introduced as zinc nitrate (Zn(NO3)2) in the water of hydration. Compressive strength, percentage of total porosity and chemically combined water content were determined at 1, 3, 7, 28 and 90 days of hydration. The phases formed upon hydration were identified using X-ray diffraction analysis (XRD). The blended OPC contained 30 wt% cement less than OPC; however, its immobilisation efficiency for Zn2+ ions up to 120 days did not decrease. Furthermore, blended OPC showed higher compressive strength than OPC, with metakaolin showing greater enhancement than homra. The results of XRD have indicated that in both cases, OPC and blended OPC, the fixation of Zn2+ ions proceeds by way of formation of calcium zincate (CaZn2(OH)6.2H2O).
Wavelet neural network model for river flow time series
Authors: Krishna Budu , Satyaji Rao Yellamelli Ramji , Nayak Purna Chandra
Published: August 2012

A new hybrid model that combines wavelets and an artificial neural network (ANN) called the wavelet neural network (WNN) model is proposed and applied for time series modelling of river flow. Time series of daily river flow of the Malaprabha River basin (Karnataka state, India) were analysed by the WNN model. The observed time series are decomposed into sub-series using a discrete wavelet transform and then an appropriate sub-series is used as input to the neural network for forecasting hydrological variables. The hybrid model (WNN) was compared with the standard ANN and auto-regressive (AR) models. The WNN model was able to provide a good fit with the observed data, especially the peak values during testing. The benchmark results from WNN model applications show that the hybrid model produces better results than the ANN and AR models in estimating hydrograph properties.
A mixing length model for estimating channel conveyance
Authors: Horritt Matthew S. , Wright Nigel G.
Published: August 2012

This paper describes a simple, physically based mixing length model that explains the functional form of Manning's equation for mean velocity in open channels. Manning's equation has been used to describe mean velocity for over 100 years and is essentially an empirical result rather than being based on an understanding of physical processes. The model described in this paper uses Prandtl's mixing length hypothesis, with mixing length modelled at each point within the cross-section being proportional to the distance to the nearest solid boundary. The model solves equations for the along-stream velocity field using a simple numerical method on regular and irregular finite-difference meshes. The results of the model are compared with Manning's equation and the Colebrook–White formula, giving good agreement across a range of channel sizes, roughnesses and geometries. The results and comparison are used to draw useful insights into open channel flows.
Briefing: Groundwater treatment on the Olympic Park
Authors: Mead Ian , Apted James , Ketchell Nick
Published: August 2012

Following completion of the site investigation, the remediation design and soil remediation phases on the Olympic Park, the focus turned to the remediation of the underlying groundwater contamination. As with the soil, the groundwater aquifers had also been impacted by the downward migration of contamination following historic industrial activity in the area. This contamination required treatment by a number of techniques to protect both the surrounding watercourses that dissect the park and the underlying groundwater aquifers from further impact.
Onco-Nephrology
Authors: Cambier Jean-François , Ronco Pierre
Published: August 2012

Glomerular diseases occurring in the course of malignancies remain rare. Diverse glomerular lesions can be observed in a variety of neoplasms and involve different pathophysiologic links between the glomerulopathy and the cancer. The pathophysiology of solid tumor–associated glomerulopathies remains obscure, whereas in hematologic malignancy–induced paraneoplastic glomerulopathies, a molecular link can usually be demonstrated. The aim of this review is to provide an update on glomerular diseases associated with carcinoma and hematologic malignancies, covering epidemiology, pathophysiology, clinical presentation, and therapy. Special emphasis will be placed on the potential usefulness of novel biomarkers, such as antiphospholipase A2 receptor antibodies, for the diagnosis of membranous nephropathy, and on new associations and recent entities, including (proliferative) GN with nonorganized monoclonal immunoglobulin deposits and myeloproliferative neoplasm–related glomerulopathy.
Financial Information Globalization and Foreign Investment Decisions
Authors: Amiram Dan
Published: August 2012

This paper investigates the association between the adoption of international accounting standards and foreign investment decisions. Prior research suggests that information asymmetries between local and foreign investors and behavioral biases caused by unfamiliarity of the foreign markets contribute to investors preferring to invest in their home markets. Because one of the goals of the adoption of international accounting standards is to establish a high-quality, internationally familiar set of accounting standards, I predict that foreign investments will increase in countries that adopted International Financial Reporting Standards (IFRS) after the adoption and that this increase is driven by the familiarity of IFRS. I find that foreign equity portfolio investments (FPI) increase in countries that adopt IFRS. More importantly, I find that this relation is driven by foreign investors from countries that also use IFRS. Moreover, the effect of accounting familiarity is more pronounced when investor and investee countries share language, legal origin, culture, and region. I also find that countries with lower corruption and better investor protection experience larger increases in FPI after they adopt IFRS relative to other IFRS users. These findings are consistent with the hypothesis that familiar accounting information drives foreign investment decisions.
Postmortem Vascular Pathology in PHACES Syndrome: A Case Report
Authors: Chad Lauren , Dubinski William , Hawkins Cynthia , Pope Elena , Bernstein Stacey , Chiasson David
Published: August 2012

This case describes the clinical course and autopsy findings of a 5-year-old girl with PHACES syndrome. While the etiopathogenesis of this condition is not yet understood, the pathological changes documented support the concept that the primary defect in PHACES syndrome is an arteriopathy.
Age of the Younger Laxá Lava and Lake Mývatn, Northern Iceland, Determined by AMS Radiocarbon Dating
Authors: Hauptfleisch Ulf , Einarsson Árni
Published: August 2012

Lake Mývatn and several smaller lakes in northern Iceland were formed by the large Holocene lava flow of the Younger Laxá Lava (YLL). The age of the YLL was estimated by tephrochronology at 1800–2300 BP (Thorarinsson 1951). Conventional radiocarbon dating of charred vegetation beneath the YLL (Thorarinsson 1964) yielded uncalibrated ages of 1940 ± 27014C yr BP (Yale), 2110 ± 14014C yr BP (Copenhagen), and 1990 ± 5014C yr BP (Winnipeg). Ongoing palcolimnological research at Lake Mývatn requires a more precise age estimation of the YLL. Charcoal samples from beneath the YLL were collected at Presthvammur in 2007 and analyzed by accelerator mass spectrometry (AMS)14C measurements. The reliability of the conventional14C ages of the samples Yale, Copenhagen, and Winnipeg was re-evaluated, applying criteria from Pettit et al. (2003) and Graf (2009). The result of AMS14C measurement (2170 ± 38 cal yr BP) underpins the local tephrochronology and provides a reliable age of the YLL and Lake Mývatn.
New AMS Radiocarbon Dates from Late Pleistocene Mastodons and Mammoths in New York State, USA
Authors: Feranec Robert S , Kozlowski Andrew L
Published: August 2012

During the Last Glacial Maximum (LGM) about 25,000 yr ago, the area of what is now New York State (USA) was almost entirely covered by the Laurentide Ice Sheet (LIS; Dyke et al. 2002). Subsequent habitation of this area after the melting of the LIS necessitates dispersal of fauna, and the timing of the dispersal of particular species may aid in the understanding of how the modern ecosystems of New York were assembled. Mastodons and mammoths represent the most abundant post-LGM Pleistocene megafauna recovered in New York. However, many of the specimens have not been dated. This paper presents a set of dates from bone and tooth dentine collagen of late Pleistocene mastodon (n = 7) and mammoth (n = 3) specimens housed in the Vertebrate Paleontology Collections at the New York State Museum, Albany, New York, USA.
Reconceiving the Chronology of Inca Imperial Expansion
Authors: Ogburn Dennis E
Published: August 2012

The basic chronology of Inca imperial expansion in Andean South America derives from historical accounts from the Spanish Colonial era, but several issues with this traditional chronology have arisen in recent decades. Advances in radiocarbon dating and calibration now give us some ability to refine or rebuild the chronology, and guidelines for obtaining the most useful dates are discussed. Dates recently obtained from the site of Chamical in the southern highlands of Ecuador are evaluated according to those guidelines, and they suggest Inca expansion to the north began 1 to 2 decades earlier than allowed in the traditional chronology. The chronology of Inca expansion presented in the Spanish chronicles is called into question by these and other dates, and by a reconsideration of the nature of sources of Inca history utilized by Spanish writers. Evidence suggests a primary Inca form of recording provincial conquests resulted in lists that were ordered geographically. However, those records were interpreted by colonial writers as being chronologically ordered, which led to written histories of Inca expansion that are not consistent with the actual historical sequence of events. As a result, the preferred approach to building a chronology of Inca expansion should be based on14C dates, with historical sources used to supplement rather than structure the timeline.
Fixed points and iterations of mean-type mappings
Authors: Matkowski Janusz
Published: August 2012

Let (X, d) be a metric space and T: X → X a continuous map. If the sequence (T
n)n∈ℕ of iterates of T is pointwise convergent in X, then for any x ∈ X, the limit $$\mu _T (x) = \mathop {\lim }\limits_{n \to \infty } T^n (x)$$ is a fixed point of T. The problem of determining the form of µT leads to the invariance equation µT ○ T = µT, which is difficult to solve in general if the set of fixed points of T is not a singleton. We consider this problem assuming that X = I
p, where I is a real interval, p ≥ 2 a fixed positive integer and T is the mean-type mapping M =(M
1,...,M
p) of I
p. In this paper we give the explicit forms of µM for some classes of mean-type mappings. In particular, the classical Pythagorean harmony proportion can be interpreted as an important invariance equality. Some applications are presented. We show that, in general, the mean-type mappings are not non-expansive.
Invariant sets and Knaster-Tarski principle
Authors: Leśniak Krzysztof
Published: August 2012

Our aim is to point out the applicability of the Knaster-Tarski fixed point principle to the problem of existence of invariant sets in discrete-time (multivalued) semi-dynamical systems, especially iterated function systems.
Low temperature measurements by infrared spectroscopy in CoFe2O4 ceramic
Authors: Bujakiewicz-Korońska Renata , Hetmańczyk Łukasz , Garbarz-Glos Barbara , Budziak Andrzej , Kalvane Anna , Bormanis Karlis , Drużbicki Kacper
Published: August 2012

This paper presents results of new far-infrared and middle-infrared measurements (wavenumber range of 4000–100 cm−1) of the CoFe2O4 ceramic in the temperature range from 300 K to 8 K. The band positions and their shapes remain constant across the wide temperature range. The quality of the sample was investigated by X-ray, EDS and EPMA studies. The CoFe2O4 retains the cubic structure (Fd - 3m) across the temperature range from 85 K to 360 K without any traces of distortion. Based on current knowledge the polycrystalline CoFe2O4 does not exhibit any phase transitions across the temperature range from 8 K to 300 K.
Observation of electromagnetically induced transparency in a ring cavity
Authors: Wu E. , Ma Yong-Hong , Han Xiang-Gang
Published: August 2012

A scheme to observe Electromagnetically induced transparency (EIT) in an optomechanical system is proposed in the current paper. We treat a narrowband squeezed field as the weak probe field. We find that EIT dips exist in the output field. Moreover, the dependence of the EIT dips on the effective cavity detuning Δ and the input power ζ are explored. We show that the width of the EIT dips can be controlled by the parameters ξ and the detuning Δ.
Continuous sorption of synthetic dyes on dried biomass of microalga Chlorella pyrenoidosa
Authors: Horník Miroslav , Šuňovská Anna , Partelová Denisa , Pipíška Martin , Augustín Jozef
Published: August 2012

The sorption of thioflavine T (TT) and malachite green (MG) cationic synthetic dyes on dried biomass of green microalga (Chlorella pyrenoidosa) immobilised in polyurethane foam under continuous column systems conditions using spectrophotometric methods of detection was investigated. Data characterising the sorption of TT and MG on microalgal biomass immobilised in polyurethane foam in a column system from single (C 0 = 25 μmol dm−3) or binary equimolar (C 0 = 25 μmol dm−3) dye solutions in the form of breakthrough curves were well described by the Thomas (R 2 = 0.994–0.912), Yoon-Nelson (R 2 = 0.994–0.911), and Clark (R 2 = 0.993–0.911) models. Useful parameters characterising the sorption column system were obtained from these mathematical models. The Thomas model, in particular, provided the Q max (maximal sorption capacity in μmol g−1) parameter for characterisation of biosorbent and also for evaluation of competitive effects in the TT and MG dyes sorption. For the purposes of biomass regeneration, a one-step desorption of the dyes studied from the microalgal biomass in batch and continuous column systems was performed. Efficiency of TT desorption from microalgal biomass increased in the order: deionised H2O (50.7 %), 99.5 vol. % 1,4-dioxane (67 %), 20 mmol dm−3 NiCl2 (83 %), 96 vol. % ethanol (85 %), 0.1 mol dm−3 HCl (89 %), 1 mol dm−3 acetic acid (89 %). In the case of MG, the desorption efficiency increased in the order: deionised H2O (13 %), 20 mmol dm−3 NiCl2 (50 %), 0.1 mol dm−3 HCl (91 %), 99.5 vol. % 1,4-dioxane (94 %), 1 mol dm−3 acetic acid (99 %), 96 vol. % ethanol (> 99 %). The presence of carboxyl, phosphoryl, amino, and hydroxyl groups, the important functional groups for sorption of cationic xenobiotics, was also confirmed on the algae biomass surface by potentiometric titration and ProtoFit modelling software. The data obtained showed that the dried immobilised algae biomass could be used as a sorbent for removing toxic xenobiotics from liquid wastewaters or contaminated waters and also presenting the possibilities of mathematical modelling of sorption processes in continuous column systems in order to obtain important parameters for use in practice.
Experimental and analytical study of high velocity impact on Kevlar/Epoxy composite plates
Authors: Sikarwar Rahul , Velmurugan Raman , Madhu Velmuri
Published: August 2012

In the present study, impact behavior of Kevlar/Epoxy composite plates has been carried out experimentally by considering different thicknesses and lay-up sequences and compared with analytical results. The effect of thickness, lay-up sequence on energy absorbing capacity has been studied for high velocity impact. Four lay-up sequences and four thickness values have been considered. Initial velocities and residual velocities are measured experimentally to calculate the energy absorbing capacity of laminates. Residual velocity of projectile and energy absorbed by laminates are calculated analytically. The results obtained from analytical study are found to be in good agreement with experimental results. It is observed from the study that 0/90 lay-up sequence is most effective for impact resistance. Delamination area is maximum on the back side of the plate for all thickness values and lay-up sequences. The delamination area on the back is maximum for 0/90/45/-45 laminates compared to other lay-up sequences.
Lumbar load attenuation for rotorcraft occupants using a design methodology for the seat impact energy-absorbing system
Authors: Moradi Rasoul , Beheshti Hamid , Lankarani Hamid
Published: August 2012

Aircraft occupant crash-safety considerations require a minimum cushion thickness to limit the relative vertical motion of the seat-pelvis during high vertical impact loadings in crash landings or accidents. In military aircraft and helicopter seat design, due to the potential for high vertical accelerations in crash scenarios, the seat system must be provided with an energy absorber to attenuate the acceleration level sustained by the occupants. Because of the limited stroke available for the seat structure, the design of the energy absorber becomes a trade-off problem between minimizing the stroke and maximizing the energy absorption. The available stroke must be used to prevent bottoming out of the seat as well as to absorb maximum impact energy to protect the occupant. In this study, the energy-absorbing system in a rotorcraft seat design is investigated using a mathematical model of the occupant/seat system. Impact theories between interconnected bodies in multibody mechanical systems are utilized to study the impact between the seat pan and the occupant. Experimental responses of the seat system and the occupant are utilized to validate the results from this study for civil and military helicopters according to FAR 23 and 25 and MIL-S-58095 requirements. A model for the load limiter is proposed to minimize the lumbar load for the occupant by minimizing the relative velocity between the seat pan and the occupant’s pelvis. The modified energy absorber/load limiter is then implemented for the seat structure so that it absorbs the energy of impact in an effective manner and below the tolerable limit for the occupant in a minimum stroke. Results show that for a designed stroke, the level of occupant lumbar spine injury would be significantly attenuated using this modified energy-absorber system.
Effects of Vehicle Volume and Lane Closure Length on Construction Road User Costs in Rural Areas
Authors: Watts Mikkel Y. , Zech Wesley C. , Turochy Rod E. , Holman Derek B. , LaMondia Jeffrey J.
Published: August 2012

The objective of this paper is to analyze the effects that vehicle volumes and lane closure lengths have on road user costs (RUCs) in rural freeway work zones. This paper presents a methodology developed to estimate RUCs for a rural four-lane freeway under construction with a single lane closure. Although the scenario presented is limited in its application to rural freeway construction projects, the methodology presented can be applied for any road construction project. Three tools have been developed as a result of this research: (a) a RUC template designed to calculate RUCs for a location on the basis of vehicle volumes, lane closure lengths, and speed values; (b) design graphs that practitioners can quickly reference to estimate RUCs for rural four-lane freeways with a single lane closure; and (c) regression equations derived from this research to quickly estimate RUCs. A practical and repeatable design method for estimating RUCs uses the results of this research. The design method can be used when time-based contractual provisions are developed on the basis of RUCs that are to be included in construction contracts for determining total project costs. When the method is used properly, it provides state highway agencies with a useful, justifiable way to calculate RUCs for single lane closure scenarios that can be used to develop incentive and disincentive provisions in rural roadway construction contracts.
Value of Tablet Computers in Transportation Construction Inspection
Authors: Asbahan Rania E. , DiGirolamo Paul
Published: August 2012

The use of tablet computers (TCs) in construction provides more accurate, reliable, and timely project information to field inspectors and enables them to gather and transmit up-to-date project information remotely from the field. This study investigates the value of inspectors' use of TCs on transportation construction projects conducted in Pennsylvania. This study's objective was to monitor the performance changes of inspectors once they started using TCs in their daily activities. The inspectors' typical jobsite functions were separated into five typical daily tasks and activities: general inspection, system inspection, paperwork, document research and meetings, and other tasks. Performance was monitored by the time required to perform each task and activity before and after the introduction of the TC. Results indicated that using TCs reduced the amount of time the inspector typically needed for the document research task, which included looking up information to reply to the contractor's queries and determining adherence to specifications. This same time was transferred onto the general inspection task, which consisted of observing ongoing construction activities. Although this time saving does not affect progress of the overall project, it allows inspectors to remain on the jobsite where they can perform their primary duties. Some weather-related technical limitations of the device were found to affect productivity. Precautions need to be taken to keep the device in an environment with temperatures that are within its operating temperature range.
Benefits of Three- and Four-Dimensional Computer-Aided Design Model Applications for Review of Constructability
Authors: O'Brien William J. , Gau Pierre , Schmeits Cameron , Goyat Jean , Khwaja Nabeel
Published: August 2012

This paper presents recent developments and applications of three- (3-D) and four-dimensional (4-D) modeling on two transportation projects and their added value for constructability reviews. Transportation projects are characterized by challenges, such as design complexity, right-of-way acquisition, utility relocation, and traffic management, which truly need to be addressed by constructability reviews so as to make projects successful by minimizing delays, cost overruns, change orders, and so on. The 3-D and 4-D computer-aided drafting (CAD) models are new emerging tools that can tremendously aid constructability reviews. Although the models are extensively used in building projects for this purpose, their use in transportation projects is limited. The 3-D and 4-D CAD models in building projects could also be applied to transportation projects. The 3-D and 4-D CAD model applications developed for the two transportation projects in this paper emphasize the value added by this new technology to communication, technical design checking, construction planning, and work area management applied to transportation projects.
Effective Tools for Projects Delivered by Construction Manager–General Contractor Method
Authors: West Nicola , Gransberg Douglas D. , McMinimee James
Published: August 2012

Construction manager–general contractor (CMGC) is an alternative project delivery method that is fast becoming more prevalently used to accelerate the delivery of highway projects. FHWA's Every Day Counts program is encouraging state departments of transportation (DOTs) to adopt CMGC as a tool to deliver badly needed rapid renewal projects. As part of the program, a CMGC Peer Exchange conference was held in June 2011 in Salt Lake City, Utah. This paper synthesizes the tools used in implementing CMGC project delivery that were reported in those conference presentations by state DOTs with CMGC experience. That information is compared with similar information found in the literature to document the current state-of-the-practice in CMGC highway project delivery. It is concluded that jointly managing risk and developing a collaborative business climate are the two most important aspects of successful CMGC project delivery.
Nondestructive Tests of Thickness Measurements for Concrete Pavements
Authors: Grove Jim , Jones Kevin , Ye Dan , Gudimettla Jagan M.
Published: August 2012

Magnetic pulse induction can be used to determine the thickness of concrete pavement in a nondestructive manner. This induction provides the same level of accuracy and can save time and money for state agencies when compared with coring the pavement for thickness determination. The MIT-SCAN-T2 is a commercially available device that uses magnetic pulse induction to measure pavement thickness. The technology and operation of this device are described. Field experience from various states is provided. The accuracy and the repeatability, when compared with measuring core lengths, are good on the basis of data collected to date. The advantages of this nondestructive testing are presented. A specification developed by the Iowa Department of Transportation is included. The paper also includes a discussion of other issues that may be raised when this technique is used or there is ongoing work related to implementation.
Asphalt Mixture Beams Used in Bending Beam Rheometer for Quality Control
Authors: Ho Chun-Hsing , Romero Pedro
Published: August 2012

This paper introduces the use of asphalt mixture beams in the bending beam rheometer (BBR) for quality control with a project in Utah as a case study. A good solution for quality control, the BBR test can be performed by materials laboratory staff at highway agencies and private materials laboratories because it is reasonably priced, is rugged-tested, uses limited material, is conditioned quickly, is available, and is familiar to staff at materials laboratories for everyday mix design and quality control. The paper begins with a literature review of past research work in support of using BBR tests to measure properties of asphalt mixture beams. An asphalt construction project in Utah was selected to demonstrate the applicability of using asphalt mixture beams in the BBR for quality control. Field samples obtained from the project in Utah were shipped to the laboratory, where comparisons of low-temperature properties of asphalt mixtures were done with the BBR. Results easily showed an anomaly on two paving days, when the m value (slope of the curve) was higher than normal. Because of this irregularity, further testing was initiated with the indirect tension test performed at the Asphalt Institute; the test confirmed the results from the BBR. On the basis of results and demonstration, it is clear that using asphalt mixture beams in the BBR is feasible for quality control to evaluate the performance of constructed materials. The application of using asphalt mixture beams in the BBR can be easily adopted by highway agencies to facilitate quality control operations in asphalt construction.
Stability of Curved Steel I-Girder Bridges during Construction
Authors: Sanchez T. Andres , White Donald W.
Published: August 2012

Structural stability is one of the essential aspects of the construction of curved steel I-girder bridges. The AASHTO load and resistance factor design (LRFD) bridge design specifications require the consideration of stability-critical conditions during the construction of curved I-girder bridges through checking (a) nominal initial yielding due to combined major-axis bending and flange lateral bending, (b) strength under combined major-axis and flange lateral bending, and (c) web-bend buckling. These specifications limit the flange lateral bending stress to 0.6Fy. In some cases, these rules may not be sufficient unless global second-order amplification of the lateral-torsional response is considered. In particular, structures with narrow widths and long spans may be susceptible to large second-order amplification that could compromise the overall system constructability. This paper presents analytical studies of a slender curved and skewed I-girder bridge unit that exhibited difficulties during the placement of the concrete deck. The results of approximate one-and two-dimensional analyses of the construction phase are compared with refined three-dimensional finite element solutions to highlight their differences. Guidelines are provided for handling cases in which the slender geometry of the structure may be an important constructability consideration.
Food Insecurity in Canadian Adults: Receiving Diabetes Care
Authors: Galesloot Suzanne , McIntyre Lynn , Fenton Tanis , Tyminski Sheila
Published: August 2012

Purpose: The prevalence of adult-level household food insecurity was examined among clients receiving outpatient diabetes health care services.

Methods: Participants were adults diagnosed with diabetes mellitus, who attended individual counselling sessions at Calgary's main clinic from January to April 2010. Clinicians were trained to administer the Household Food Security Survey Module (HFSSM), and did so with clients’ assent during their scheduled sessions.

Results: The prevalence of adult-level household food insecurity among 314 respondents was 15.0% (95% confidence interval [CI], 11.2 to 19.4); 6.7% (95% CI, 4.2 to 10.0) of clinic attendees were categorized as severely food insecure. The comparable rates obtained in Alberta in 2007 using the same instrument (HFSSM) were 5.6% and 1.2%, respectively.

Conclusions: Household food insecurity rates among individuals with diabetes in active care are higher than rates reported in Canadian population surveys. Severe food insecurity, indicating reduced food intake and disrupted eating patterns, may affect this population's ability to follow a pattern of healthy eating necessary for effective diabetes management. This study reinforces the importance of assessing clients’ inability to access food because of financial constraints, and indicates that screening with a validated measure may facilitate identification of clients at risk.
Assessment of antiangiogenic effect of imatinib mesylate on vestibular schwannoma tumors using in vivo corneal angiogenesis assay
Authors: Yener Ulaş , Avsar Timucin , Akgün Emel , Şeker Aşkın , Bayri Yaşar , Kılıç Türker
Published: August 2012

Object

Angiogenesis and the platelet-derived growth factor (PDGF) pathway are active in the pathogenesis of vestibular schwannomas (VSs). The purpose of this study was to test whether imatinib mesylate (Gleevec), a PDGF receptor (PDGFR) blocker, reduces angiogenic capacity in sporadic VS and in VS associated with neurofibromatosis Type 2 (NF2) using a corneal angiogenesis assay.

Methods

From 121 VS tissue samples stored in the tumor bank at the Marmara University Institute of Neurological Sciences, 10 samples (6 from sporadic cases, 4 from NF2-associated cases) were selected at random for use in this study. Expression of PDGF-A and PDGF-B and their receptors was evaluated in sporadic and NF2-associated VS as well as in glioblastoma (GBM) and normal brain tissue by means of immunohistochemistry and Western blot analysis. Corneal angiogenesis assay was then used to evaluate the angiogenic capacity of tissue specimens from sporadic and NF2-associated VS with and without imatinib treatment as well as positive and negative controls (GBM and normal brain tissue).

Results

The angiogenic potential of the sporadic and NF2-associated VS tumor tissue differed significantly from that of the positive and negative control tissues (p <0.05). Furthermore, NF2-associated VS showed significantly lower angiogenic potential than sporadic VS (p <0.05). Imatinib treatment significantly reduced the angiogenic potential in both the sporadic VS and the NF2-associated VS groups. The level of PDGF-A and PDGFR-α as well as PDGF-B and PDGFR-β expression in sporadic VS and NF2-associated VS also differed significantly (p <0.05) from the levels in controls. Additionally the level of PDGFR-β was significantly higher in sporadic VS than in NF2-associated VS (p <0.05).

Conclusions

The findings of this study indicate that NF2-associated VS has significantly more angiogenic potential than sporadic VS and normal brain tissue. Additionally, imatinib reduces the angiogenic activity of both sporadic and NF2-associated VS. The authors conclude that imatinib may be a potential treatment for VS, especially for NF2-associated lesions that cannot be cured with resection or radiosurgery.
Does adjuvant external-beam radiotherapy improve outcomes for nonbenign meningiomas? A Surveillance, Epidemiology, and End Results (SEER)–based analysis
Authors: Stessin Alexander M. , Schwartz Allie , Judanin Grigorij , Pannullo Susan C. , Boockvar John A. , Schwartz Theodore H. , Stieg Philip E. , Wernicke A. Gabriella
Published: August 2012

Object

The aim of this study was to examine the effect of postoperative external-beam radiation therapy (EBRT) on disease-specific survival in patients with nonbenign meningiomas.

Methods

The Surveillance, Epidemiology, and End Results (SEER) database from 1988 to 2007 was queried for cases of resected Grades II (atypical) and III (malignant) meningioma. Disease-specific survival outcomes were determined using Kaplan-Meier survival analysis and Cox proportional hazards models. Logistic regression analysis was used to determine the likelihood of receiving EBRT for Grade II versus Grade III. Because atypical and malignant meningiomas underwent WHO reclassification in 2000, the authors carried out an additional analysis of outcomes of these tumors from 2000 to 2008.

Results

There were 657 patients included in the analysis; of these, 244 received adjuvant radiation. Compared with patients with Grade II meningioma, patients with Grade III disease were 41.9% more likely to receive EBRT after gross-total resection and 36.7% more likely to receive it after subtotal resection (95% CI 0.58–3.26). Controlling for grade, extent of resection, size and anatomical location of the tumor, year of diagnosis, race, age, and sex, adjuvant EBRT did not impart a survival benefit (HR 1.492; 95% CI 0.827–2.692). There was also no survival advantage to EBRT in an analysis of cases diagnosed after the WHO 2000 reclassification of meningiomas (HR 0.828; 95% CI 0.350–1.961).

Conclusions

The results of this population-based retrospective analysis demonstrate that the role of radiation remains unclear. They underscore the need for randomized prospective clinical trials to assess the usefulness of adjuvant EBRT in Grades II and III meningioma so as to define more precisely the subset of patients who may benefit from the addition of adjuvant radiation.
Giant anterior clinoidal meningiomas: surgical technique and outcomes
Authors: Attia Moshe , Umansky Felix , Paldor Iddo , Dotan Shlomo , Shoshan Yigal , Spektor Sergey
Published: August 2012

Object

Surgery for giant anterior clinoidal meningiomas that invade vital neurovascular structures surrounding the anterior clinoid process is challenging. The authors present their skull base technique for the treatment of giant anterior clinoidal meningiomas, defined here as globular tumors with a maximum diameter of 5 cm or larger, centered around the anterior clinoid process, which is usually hyperostotic.

Methods

Between 2000 and 2010, the authors performed 23 surgeries in 22 patients with giant anterior clinoidal meningiomas. They used a skull base approach with extradural unroofing of the optic canal, extradural clinoidectomy (Dolenc technique), transdural debulking of the tumor, early optic nerve decompression, and early identification and control of key neurovascular structures.

Results

The mean age at surgery was 53.8 years. The mean tumor diameter was 59.2 mm (range 50–85 mm) with cavernous sinus involvement in 59.1% (13 of 22 patients). The tumor involved the prechiasmatic segment of the optic nerve in all patients, invaded the optic canal in 77.3% (17 of 22 patients), and caused visual impairment in 86.4% (19 of 22 patients). Total resection (Simpson Grade I or II) was achieved in 30.4% of surgeries (7 of 23); subtotal and partial resections were each achieved in 34.8% of surgeries (8 of 23). The main factor precluding total removal was cavernous sinus involvement. There were no deaths. The mean Glasgow Outcome Scale score was 4.8 (median 5) at a mean of 56 months of follow-up. Vision improved in 66.7% (12 of 18 patients) with consecutive neuroophthalmological examinations, was stable in 22.2% (4 of 18), and deteriorated in 11.1% (2 of 18). New deficits in cranial nerve III or IV remained after 8.7% of surgeries (2 of 23).

Conclusions

This modified surgical protocol has provided both a good extent of resection and a good neurological and visual outcome in patients with giant anterior clinoidal meningiomas.
Increased mortality in patients with severe traumatic brain injury treated without intracranial pressure monitoring
Authors: Farahvar Arash , Gerber Linda M. , Chiu Ya-Lin , Carney Nancy , Härtl Roger , Ghajar Jamshid
Published: August 2012

Object

Evidence-based guidelines recommend intracranial pressure (ICP) monitoring for patients with severe traumatic brain injury (TBI), but there is limited evidence that monitoring and treating intracranial hypertension reduces mortality. This study uses a large, prospectively collected database to examine the effect on 2-week mortality of ICP reduction therapies administered to patients with severe TBI treated either with or without an ICP monitor.

Methods

From a population of 2134 patients with severe TBI (Glasgow Coma Scale [GCS] Score <9), 1446 patients were treated with ICP-lowering therapies. Of those, 1202 had an ICP monitor inserted and 244 were treated without monitoring. Patients were admitted to one of 20 Level I and two Level II trauma centers, part of a New York State quality improvement program administered by the Brain Trauma Foundation between 2000 and 2009. This database also contains information on known independent early prognostic indicators of mortality, including age, admission GCS score, pupillary status, CT scanning findings, and hypotension.

Results

Age, initial GCS score, hypotension, and CT scan findings were associated with 2-week mortality. In addition, patients of all ages treated with an ICP monitor in place had lower mortality at 2 weeks (p = 0.02) than those treated without an ICP monitor, after adjusting for parameters that independently affect mortality.

Conclusions

In patients with severe TBI treated for intracranial hypertension, the use of an ICP monitor is associated with significantly lower mortality when compared with patients treated without an ICP monitor. Based on these findings, the authors conclude that ICP-directed therapy in patients with severe TBI should be guided by ICP monitoring.
Progressive symptomatic increase in the size of choroidal fissure cysts
Authors: Tubbs R. Shane , Muhleman Mitchel , McClugage Samuel G. , Loukas Marios , Miller Joseph H. , Chern Joshua J. , Rozzelle Curtis J. , Oakes W. Jerry , Cohen-Gadol Aaron A.
Published: August 2012

Cysts of the choroidal fissure are often incidentally identified. Symptoms from such cysts appear to be exceedingly rare. Herein, the authors report a case series of symptomatic enlargement of choroidal fissure cysts that were surgically treated. Although cysts of the choroidal fissure do not normally become symptomatic, the neurosurgeon should be aware of such a complication. Based on the authors' experience, surgical fenestration of such cysts has good long-term results.
Long-term results of cystoperitoneal shunt placement for the treatment of arachnoid cysts in children
Authors: Zhang Bin , Zhang Yuqi , Ma Zhenyu
Published: August 2012

Object

The authors present a single-institution experience in shunt treatment for arachnoid cysts (ACs).

Methods

Between January 2003 and January 2005, 62 patients with ACs underwent cystoperitoneal (CP) shunt placement at the authors' institution. All patients were evaluated with CT or MRI studies and had regular follow-up examinations.

Results

Forty-six cysts (74%) were within the sylvian fissure, 8 (13%) were in the cerebral convexity, and 8 (13%) were infratentorial. A CP shunt was placed in all patients. Follow-up imaging studies showed that 59 (95%) of 62 ACs reduced in size during a mean postoperative follow-up period of 6.5 years (range 6–8 years). Although a CP shunt was effective in achieving early obliteration, shunt dependency occurred within the patient group (13%). Shunt revision for various reasons was performed in 16 patients (26%).

Conclusions

Shunt placement is a safe and effective surgical treatment for symptomatic ACs in children, although efforts should be made to decrease complications in the procedure.
Application of diffusion tensor tractography in pediatric optic pathway glioma
Authors: Lober Robert M. , Guzman Raphael , Cheshier Samuel H. , Fredrick Douglas R. , Edwards Michael S. B. , Yeom Kristen W.
Published: August 2012

Object

Magnetic resonance imaging is commonly used in diagnosis and surveillance for optic pathway glioma (OPG). The authors investigated the role of diffusion tensor (DT) tractography in assessing the location of visual pathway fibers in the presence of tumor.

Methods

Data in 10 children with OPG were acquired using a 3T MRI generalized autocalibrating parallel acquisitions DT–echo planar imaging sequence (25 isotropic directions with a b value of 1000 seconds/mm2, slice thickness 3 mm). Fiber tractography was performed, with seed regions placed within the optic chiasm and bilateral nerves on the coronal plane, including the tumor and surrounding normal-appearing tissue. Tracking was performed with a curvature threshold of 30°.

Results

For prechiasmatic lesions, fibers either stopped abruptly at the tumor or traversed abnormally dilated nerve segments. Similar findings were seen with chiasmatic lesions, with an additional arrangement in which fibers diverged around the tumor. For each patient, DT tractography provided additional information about visual fiber arrangement in relation to the tumor that was not evident by using conventional MRI methods. Retrospective reconstruction of visual fibers in 1 patient with new postoperative hemianopia revealed an unexpected superior displacement of the optic tract that might have been helpful information had it been applied to preoperative planning or surgical navigation.

Conclusions

Optic pathway DT tractography is feasible in patients with OPG and provides new information about the arrangement of visual fibers in relation to tumors that could be incorporated into surgical navigation for tumor biopsy or debulking procedures.
Comparison of expandable and fixed interbody cages in a human cadaver corpectomy model, Part I: endplate force characteristics
Authors: Pekmezci Murat , Tang Jessica A. , Cheng Liu , Modak Ashin , McClellan R. Trigg , Buckley Jenni M. , Ames Christopher P.
Published: August 2012

Object

Expandable cages are becoming more popular due in large part to their versatility, but subsidence and catastrophic failure remain a concern. One of the proposed reasons of failure is edge loading of the endplate caused by a mismatch between the sagittal alignment of the motion segment and cage. This in vitro analysis investigates the endplate forces characteristic of expandable and fixed interbody cages in a single-level human cadaver corpectomy model.

Methods

Ten human thoracolumbar spines (T10–L2, L3–5) were biomechanically evaluated following a single-level corpectomy that was reconstructed with an expandable or fixed cage. Fixed cages were deployed with the best-fitting end cap combination, whereas expandable cages were deployed in normal, hypolordotic, and hyperlordotic alignment scenarios. The endplate forces and contact area were measured with a pressure measurement system, and the expansion torque applied by the surgeon was measured with a custom-made insertion device.

Results

The contact areas of the expandable cages were, in general, higher than those of the fixed cages. The endplate forces of the expandable cages were similar to those of the fixed cages in the normal alignment scenario. Higher endplate forces were observed in the hyperlordotic scenario, whereas the endplate forces in the hypolordotic and normal alignment scenarios were similar. There was no correlation with the expansion torque and the final endplate forces.

Conclusions

Expandable cages resulted in consistently higher contact area and endplate forces when compared with the fixed cages. Because the expansion torque does not correlate with the final endplate forces, surgeons should not rely solely on tactile feedback during deployment of these cages.
Surgical management of cervical radiculopathy caused by redundant vertebral artery loop
Authors: Hage Ziad A. , Amin-Hanjani Sepideh , Wen Dennis , Charbel Fady T.
Published: August 2012

In this article, the authors describe the case of a 27-year-old female presenting with a 2-year history of neck pain and radiculopathy attributable to compression of the right C-7 nerve root by tortuosity of the vertebral artery at the level of the C6–7 cervical foramina. An anterolateral approach to the transverse foramen was used to perform a vascular decompression to decompress the nerve root. The procedure was uneventful, and the patient woke up with almost all of her symptoms resolved. The authors also include a literature review of techniques performed in this setting, showing that multiple surgical approaches can be used and should be tailored to the patient symptoms and lesion characteristics.
Evaluation of Two Cloud Parameterizations and Their Possible Adaptation to Arctic Climate Conditions
Authors: Klaus Daniel , Dorn Wolfgang , Dethloff Klaus , Rinke Annette , Mielke Moritz
Published: August 2012

Based on the atmospheric regional climate model HIRHAM5, the single-column model version HIRHAM5-SCM was developed and applied to investigate the performance of a relative humidity based (RH-Scheme) and a prognostic statistical cloud scheme (PS-Scheme) in the central Arctic. The surface pressure as well as dynamical tendencies of temperature, specific humidity, and horizontal wind were prescribed from the ERA-Interim data set to enable the simulation of a realistic annual cycle. Both modeled temperature and relative humidity profiles were validated against radio soundings carried out on the 35th North Pole drifting station (NP-35). Simulated total cloud cover was evaluated with NP-35 and satellite-based ISCCP-D2 and MODIS observations. The more sophisticated PS-Scheme was found to perform more realistically and matched the observations better. Nevertheless, the model systematically overestimated the monthly averaged total cloud cover. Sensitivity studies were conducted to assess the effect of modified “tuning” parameters on cloud-related model variables. Two tunable parameters of the PS-Scheme and six tuning parameters contained in the cloud microphysics were analyzed. Lower values of the PS-Scheme adjustment parameter q0, which defines the shape of the symmetric beta distribution (acting as probability density function), as well as higher values of the cloud water threshold CWmin or autoconversion rate γ1 are able to reduce the overestimation of Arctic clouds. Furthermore, a lower cloud ice threshold γthr, which controls the Bergeron–Findeisen process, improves model cloudiness and the ratio of liquid to solid water content.