bluuebunny/crossref_metadata_2025 huggingface dataset:
Oseltamivir treatment of mice before or after mild influenza infection reduced cellular and cytokine inflammation in the lung
Authors: Wong Zi Xin , Jones Jessica E. , Anderson Gary P. , Gualano Rosa C.
Published: March 2011

Please cite this paper as: Wong et al. (2011) Oseltamivir treatment of mice before or after mild influenza infection reduced cellular and cytokine inflammation in the lung. Influenza and Other Respiratory Viruses 5(5), 343–350.

Background  Lung inflammation is a critical determinant of influenza infection outcomes but is seldom evaluated in animal studies of oseltamivir (OS), which have focused on viral titre and survival.

Objectives  To study the effects of pre‐ and post‐infection dosing with OS on viral replication and inflammation in a mouse model of non‐lethal influenza infection.

Methods  BALB/c mice were infected with a laboratory‐adapted H3N1 strain of influenza. In pre‐dosing studies, OS was gavaged twice daily (1 and 10 mg/kg/day) from 4 hours prior to infection and continuing for 5 days (d) post‐infection (p.i). In the second post‐infection dosing study, dosing at 10 mg/kg/day began at 24–48 hours p.i. Mice were dissected at d3, d5 and d7 p.i. (pre‐dosing study) and d5 p.i. (post‐dosing study). Lung viral titres were determined by plaque assay. Bronchoalveolar lavage fluid (BALF) was collected and used for the quantitation of inflammatory cells and mediators.

Results  Pre‐infection dosing of OS reduced total cells, neutrophils and macrophages in BALF. With pre‐ or post‐infection dosing, the pro‐inflammatory mediators TNF‐α, IL‐1β, IL‐6 and granulocyte–macrophage colony‐stimulating factor, the neutrophil chemokines keratinocyte‐derived chemokine and MIP‐1α and the macrophage chemokine MCP‐1 were reduced in BALF. Pre‐dosing with 1 mg/kg OS did not reduce viral titres, while 10 mg/kg slightly reduced viral titres at d3 and d5 p.i.

Conclusions  Oseltamivir reduced the inflammatory response to influenza when given pre‐ or post‐infection. This anti‐inflammatory effect may contribute to the clinical benefit of OS.
Scaling up Instance‐Based Learning Theory to Account for Social Interactions
Authors: Gonzalez Cleotilde , Martin Jolie M.
Published: April 2011

Traditional economic theory often describes real‐world social dilemmas as abstract games where an individual’s goal is to maximize economic benefit by cooperating or competing with others. Despite extensive empirical work, descriptive models of human behavior in social dilemmas are lacking in both cognitive realism and predictive power. This article addresses a central challenge arising from the success of modeling individuals making decisions from experience: our ability to scale these models up to explain social interactions. We propose that models based on the instance‐based learning theory (IBLT) will help us to understand how conflictual social interactions are influenced by prior experiences of involved individuals and by information available to them during the course of interaction. We present mechanisms by which IBLT might capture the effects of social interaction with different levels of information without assuming predefined interaction strategies, but rather by assuming learning from experience.
Agency in Conflict Resolution as a Manager–Lawyer Issue: Theory and Implications for Research
Authors: Borbély Adrian
Published: April 2011

Agency theory is often used, through the principal–agent framework, to explain organizational barriers to conflict resolution, i.e., the internal reasons why parties in conflict lean so much toward adjudication, despite the availability of more efficient negotiated settlement methods. Framing business conflict resolution as a professional service, a knowledge‐intensive field in which lawyers assist the other functions of the firm in resolving difficulties encountered with other organizations, leads scholars to reconsider classical agency assumptions. This contribution proposes a manager–lawyer agency framework of conflict resolution, which recognizes the influence lawyers exert over their clients and induces a focus on the micro‐interactions among decision‐makers, in‐house legal counsels and attorneys as they coproduce response to conflict. From this theoretical effort, one may draw numerous paths for future research aiming to provide Alternative Dispute Resolution promoters with an increased understanding of within‐party agency interactions.
Primers for identification of type and other archived specimens of Aphrodes leafhoppers (Hemiptera, Cicadellidae)
Authors: BLUEMEL JOANNA K. , ANDREW KING R. , VIRANT‐DOBERLET META , SYMONDSON WILLIAM O. C.
Published: April 2011

Primers were developed for leafhoppers of the genus Aphrodes amplifying 84–244 bp fragments of the mitochondrial cytochrome oxidase subunit I gene. DNA was extracted from legs of over 100‐year‐old archived museum specimens, amplified and sequenced. The fragments contain sufficient variation to unequivocally identify the different species. The majority of the analysed museum specimens, including three specimens of the syntype series for the UK endemic species A. aestuarina (Edwards 1908), were found to have been assigned to the wrong species. This work clearly underlines the need to validate museum specimens using molecular methods where identity is in doubt, based on reliable standards for species discrimination.
Microsatellite loci for dreissenid mussels (Mollusca: Bivalvia: Dreissenidae) and relatives: markers for assessing exotic and native populations
Authors: FELDHEIM KEVIN A. , BROWN JOSHUA E. , MURPHY DOUGLAS J. , STEPIEN CAROL A.
Published: April 2011

We developed and tested 14 new polymorphic microsatellite loci for dreissenid mussels, including the two species that have invaded many freshwater habitats in Eurasia and North America, where they cause serious industrial fouling damage and ecological alterations. These new loci will aid our understanding of their genetic patterns in invasive populations as well as throughout their native Ponto‐Caspian distributions. Eight new loci for the zebra mussel Dreissena polymorpha polymorpha and six for the quagga mussel D. rostriformis bugensis were compared with new results from six previously published loci to generate a robust molecular toolkit for dreissenid mussels and their relatives. Taxa tested include D. p. polymorpha, D. r. bugensis, D. r. grimmi, D. presbensis, the ‘living fossil’Congeria kusceri, and the dark false mussel Mytilopsis leucophaeata (the latter also is invasive). Overall, most of the 24 zebra mussel (N = 583) and 13 quagga mussel (N = 269) population samples conformed to Hardy–Weinberg equilibrium expectations for the new loci following sequential Bonferroni correction. The 11 loci (eight new, three previously published) evaluated for D. p. polymorpha averaged 35.1 alleles and 0.72 mean observed heterozygosity per locus, and 25.3 and 0.75 for the nine loci (six new, three previously published) developed for D. r. bugensis. All but three of these loci successfully amplified the other species of Dreissena, and all but one also amplified Congeria and Mytilopsis. All species and populations tested were significantly divergent using the microsatellite data, with neighbour‐joining trees reflecting their evolutionary relationships; our results reveal broad utility for resolving their biogeographic, evolutionary, population and ecological patterns.
Identifying Y‐chromosomal diversity by long‐template PCR
Authors: WANDELER PETER , CAMENISCH GLAUCO
Published: April 2011

Comparing Y‐chromosomal and mitochondrial haplotype variation is a promising approach to independently investigate paternal and maternal evolutionary histories in wild mammal populations. However, the difficulty of developing male‐specific genetic markers, because of its distinctive genetic architecture and the general low level of polymorphisms observed on the Y chromosome, hampers usually an effective application of this approach. Here, we present a further method of the established Y chromosome conserved anchored tagged sequences strategy to develop Y‐chromosomal markers by screening introns of male‐specific region (MSY) genes for sequence polymorphisms. By applying long‐template PCR using target species‐specific primers, adequate sequence information of several kb in size can be obtained. We applied this method in the snow vole (Chionomys nivalis) and obtained 12.4 kb of male‐specific sequence data for nine males representing four populations in the Swiss Alps. A total of 28 single nucleotide polymorphisms, four indels (>1 bp) and one polymorphic microsatellite were identified in introns of the SMCY and DBY genes. Based on this information, we developed a Y‐chromosomal genotyping assay and identified four different paternal lineages within one local snow vole population. The method we present is straightforward and as such will probably be suitable to detect adequate Y‐chromosomal diversity in a wide range of mammalian species.
Targeting Inflammation in Cardiovascular Diseases. Still a Neglected field?
Authors: Gómez‐Guerrero Carmen , Mallavia Beñat , Egido Jesus
Published: April 2011

Prevention and treatment of atherosclerosis is still a clinical challenge in the cardiovascular medicine. The classical belief that atherosclerotic lesion development solely depends on lipid deposition has been replaced by the current concept that activation of immune and inflammatory responses plays a central role in plaque initiation and progression. In this review we summarize studies on human and genetically modified animals describing a finite number of cellular and molecular mechanisms that underlie immunoinflammation in atherosclerotic plaques. We focus on the pro‐ and antiinflammatory mediators activated during atherogenesis and the intracellular signaling pathways regulating these events. Besides the advances on established pharmacological agents, we propose potential strategies for reduction/stabilization of atherosclerotic plaques based on the clinical data in inflammatory‐associated pathologies and on the encouraging studies in experimental models of atherosclerosis. We emphasize the potential of such novel inhibitors comprising receptor antagonists, neutralizing antibodies, kinase inhibitors, peptide‐based technologies, and chemicals as emerging antiinflammatory strategies for the treatment of atherosclerotic disease complications.
Religion on Dover beach
Authors: Ireland Rowan
Published: April 2011

How does transcendental religion flourish when a secular frame sets conditions of belief? This question is put in a case study of the Catholic Newman Society at the University of Melbourne (1955–65). The Society flourished in a secular University where Charles Taylor’s ‘immanent frame’ was supposedly in place. Explanations are found in the particular spirituality nurtured in the Society and in the contingencies of Australian Catholicism in the mid‐twentieth century, but also in the conventions of secular discourse in the University. Conclusions drawn from the case are: (i) that there are elective affinities between some forms of transcendental religion and a secular context; (ii) that social science dichotomies that separate the religious and secular obviate appreciation of elective affinities and hybridisation; (iii) that there are parallels between ethnographic inquiry and inner‐worldly spirituality that may help us develop a conversational ethnography.
State‐Level Zoonotic Disease Surveillance in the United States
Authors: Scotch M. , Rabinowitz P. , Brandt C.
Published: April 2011

Most emerging infectious diseases are zoonotic, yet recent commissions have highlighted deficiencies in their surveillance. We conducted a survey to understand the needs of state agencies for zoonotic disease surveillance. The findings will hopefully support the development of biomedical informatics applications that can link animal and human data for surveillance.
Fozivudine Tidoxil as Single‐Agent Therapy Decreases Plasma and Cell‐Associated Viremia during Acute Feline Immunodeficiency Virus Infection
Authors: Fogle J.E. , Tompkins W.A. , Campbell B. , Sumner D. , Tompkins M.B.
Published: April 2011

Background: Feline immunodeficiency virus (FIV) is a lentivirus that infects domestic and wild felidae and the course of disease is similar to that of human immunodeficiency virus infection. The thymidine nucleoside analog fozivudine (FZD) tidoxil is a lipid—zidovudine (ZDV) conjugate and member of the family of nucleoside reverse transcriptase (RT) inhibitors (NRTIs).

Hypothesis: FZD administration to cats during acute FIV infection produces antiviral activity with fewer adverse effects than its parent compound ZDV (AZT).

Animals: Male, neutered cats approximately 7 months of age (n = 12).

Methods: FZD (45 mg/kg q12h, n = 6) or placebo (n = 6) was administered PO in a nonblinded trial for 6 weeks to cats infected with the NCSU1 isolate of FIV. Peripheral blood was collected preinfection and at 2, 4, and 6 weeks postinfection for CBC, evaluation of CD4+ and CD8+ cell counts by flow cytometry, and quantification of plasma and cell‐associated viremia by real time RT‐PCR.

Results: Treatment of cats with FZD during the acute stage of FIV infection decreased plasma and cell‐associated viremia during the first 2 weeks of infection, but was not protective against FIV, as all cats were infected by 6 weeks.

Conclusions: At the dosage used in this study, treatment with FZD results in a short‐term decrease in viral load with no adverse effects. Further investigation of FZD is warranted to assess pharmacokinetics, optimal dosage, and to directly compare the antiviral activity of FZD to ZDV in naturally infected cats.
Effects of verbascoside, biotechnologically purified by Syringa vulgaris plant cell cultures, in a rodent model of periodontitis
Authors: Paola Rosanna D I , Oteri Giacomo , Mazzon Emanuela , Crisafulli Concetta , Galuppo Maria , Toso Roberto D A L , Pressi Giovanna , Cordasco Giancarlo , Cuzzocrea Salvatore
Published: April 2011

Objectives

Verbascoside has previously been characterized as an effective scavenger of active free radicals and an inhibitor of lipid peroxidation. In the present study, we have investigated the effects of verbascoside from Syringa vulgaris in a rat model of ligature-induced periodontitis.

Methods

Male Sprague–Dawley rats were lightly anaesthetized with pentobarbitone (35 mg/kg). Sterile, 2-0 black braided silk thread was placed around the cervix of the lower left first molar and knotted medially. Animals received vebascoside 2 mg/kg orally, daily for 8 days.

Key findings

On the eighth day after placement of the ligature, we evaluated several markers of inflammation: (i) myeloperoxidase activity, (ii) thiobarbituric acid-reactant substance measurements, (iii) NF-κB expression, (iv) iNOS expression, (v) the nitration of tyrosine residues, (vi) activation of the nuclear enzyme poly(ADP-ribose) polymerase, (vii) Bax and Bcl-2 expression and (viii) a degree of gingivomucosal tissue injury. Oral administration of verbascoside (2 mg/kg daily for 8 days) significantly decreased all of the parameters of inflammation as described above.

Conclusions

These results demonstrate that verbascoside exerts an anti-inflammatory role during experimental periodontitis and is able to ameliorate the tissue damage associated with ligature-induced periodontitis.
The architecture of high status among Finnish youth
Authors: Caravita Simona C. S. , Pöyhönen Virpi , Rajala Irene , Salmivalli Christina
Published: April 2011

We tested the construct validity of a two‐dimensional model of high status, consisting of social acceptance and perceived popularity (hereafter, acceptance and popularity) among Finnish children and adolescents. In addition, we investigated the correlates of the two forms of high status, as well as their relations to resource control. Participants were 563 boys and girls in grades four and eight, that is, aged 10–11 and 14–15. CFA and SEM models supported the hypothesis of acceptance and popularity representing distinct, yet associated constructs that have partly different correlates. Acceptance and popularity were most closely connected among grade four students, particularly among boys. Prosocial behaviour was associated with acceptance, whereas peer‐valued characteristics (physical attractiveness, athletic ability) and aggression were related especially to popularity. Popularity, but not acceptance, was positively related to resource control.
Illustrating Interpretive Inquiry: A Reflection for Art Museum Education
Authors: Hubard Olga M.
Published: April 2011

Abstract  Acknowledging that the purpose and form of inquiry processes can vary across and within disciplines, this article focuses on interpretive inquiry: the kind of inquiry conducted to interpret works whose reading is not “rigidly pre‐established and ordained” by a set of cultural references, but rather invite “freedom of reception” (Eco 1989, 6). Through comparison of two real‐life inquiries, the author shines a light on the distinctive features of interpretive inquiry. These include a web‐like meaning making process, a reliance on analogies and metaphors, and the possibility of accepting uncertainty as part of the work’s meaning. Implications for art museum education practice are explored.
Closed‐loop spontaneous baroreflex transfer function is inappropriate for system identification of neural arc but partly accurate for peripheral arc: predictability analysis
Authors: Kamiya Atsunori , Kawada Toru , Shimizu Shuji , Sugimachi Masaru
Published: April 2011

Non‐technical summary The arterial baroreflex is a closed‐loop, negative feedback control system that senses baroreceptor pressure and controls systemic arterial pressure (AP) to attenuate perturbations in AP. The total arc of the baroreflex consists of two subsystems: the neural (baroreceptor pressure input to sympathetic nerve activity (SNA)) and peripheral (SNA input to AP) arcs. We show that although the spontaneous baroreflex transfer function obtained by closed‐loop analysis has been believed to represent the neural arc function, it is inappropriate for system identification of the neural arc but is essentially appropriate for the peripheral arc under resting condition, when compared with open‐loop transfer functions that have good predictabilities of time‐series output dynamics from input signals. Our results indicate that in the spontaneous baroreflex system under closed‐loop conditions, the peripheral arc (feedforward) function predominates over the neural arc (feedback) function, probably because of the SNA component that is independent of the baroreceptor pressure input.
Modeling Hydraulically Expanded Tube-to-Tubesheet Joint Based on General Stress-Strain Curves of Tube and Tubesheet Materials
Authors: Huang Xiaoping , Xie Tian
Published: April 2011

The strength of tube-to-tubesheet joints is crucial for the joint integrity and reliability of the tubular heat exchangers. The joint strength measured by residual contact pressure is affected by several design parameters, such as the yield strength and strain hardening of the tube and tubesheet materials, initial radial clearance between the tube and tubesheet hole, and the magnitude of the expansion. It is very important to determine the expansion pressure and the residual contact pressure in designing and manufacturing tube-to-tubesheet joints by the hydraulic expansion process. In this paper, a general strain-hardening material model and analytic expressions for calculating the expansion pressure and the residual contact pressure, considering the effect of the initial clearance and the material strain hardening, have been derived. The results predicted by the present model have been compared with the results predicted by elastic perfectly plastic model, linear strain-hardening model, and the nonlinear finite element analysis results. The comparison results show that the present analytic expressions can model the effects of strain-hardening of the materials and the clearance well. The models, such as elastic-perfect model, linear strain-hardening model, and power strain-hardening model, are the special cases of the present model. The parameters needed in the present model are determined by curve fitting of the actual tensile stress-strain data of tube and tubesheet materials, respectively.
Analytical Study of the Relaxation of Welding Residual Stress by Excessive Loading for Austenitic Stainless Steel Piping Welds
Authors: Katsuyama Jinya , Onizawa Kunio
Published: April 2011

Welding residual stress is one of the most important factors of stress corrosion cracking (SCC) for austenitic stainless steels of the pressure boundary piping in nuclear power plants. For the assessment of the integrity of piping particularly for a long-term operation, it is necessary to understand the effect of excessive loading, such as an earthquake, on the residual stress. Three-dimensional finite element analyses were performed using three-dimensional model for a 250A pipe butt weld of low-carbon stainless steel of type 316L. The welding simulation method considering the moving heat source with the double ellipsoid model was confirmed by comparing with some experimental measurements. After conducting the welding simulation and residual stress analysis, several loading patterns of bending moment and axial displacements have been applied to the model by varying amount of moment and displacement in order to study the effect of excessive loading. The analyses indicated that higher loading of bending and axial stresses caused higher relaxation on welding residual stress near piping welds. The difference in the effect of loading direction was observed for both cases. It is concluded that excessive loading to piping butt-welds has an influence on the suppression of SCC growth due to the decrease in tensile residual stress at the inner surface.
Examination of the Effect of System Pressure Ratio and Heat Recuperation on the Efficiency of a Coal-Based Gas Turbine Fuel Cell Hybrid Power Generation System With CO2 Capture
Authors: VanOsdol John , Gemmen Randall , Liese Eric
Published: March 2011

This paper examines two coal-based hybrid configurations that employ separated anode and cathode streams for the capture and compression of CO2. One configuration uses a standard Brayton cycle, and the other adds heat recuperation ahead of the fuel cell. Results show that peak efficiencies near 55% are possible, regardless of cycle configuration, including the cost in terms of energy production of CO2 capture and compression. The power that is required to capture and compress CO2 is shown to be approximately 15% of the total plant power.
Modeling of Thermoacoustic Resonators With Nonuniform Medium and Boundary Conditions
Authors: Matveev Konstantin I. , Jung Sungmin
Published: April 2011

The subject of this paper is modeling of low-amplitude acoustic fields in enclosures with nonuniform medium and boundary conditions. An efficient calculation method is developed for this class of problems. Boundary conditions, accounting for the boundary-layer losses and movable walls, are applied near solid surfaces. The lossless acoustic wave equation for a nonuniform medium is solved in the bulk of the resonator by a finite-difference method. One application of this model is for designing small thermoacoustic engines. Thermoacoustic processes in the regular-geometry porous medium inserted in resonators can be modeled analytically. A calculation example is presented for a small-scale thermoacoustic engine coupled with an oscillator on a flexing wall of the resonator. The oscillator can be used for extracting mechanical power from the engine. A nonuniform wall deflection may result in a complicated acoustic field in the resonator. This leads to across-the-stack variations of the generated acoustic power and local efficiency of thermoacoustic energy conversion.
Optimal Design of an Intermediate Support for a Beam With Elastically Restrained Boundaries
Authors: Wang D.
Published: April 2011

A straight, slender beam with elastically restrained boundaries is investigated for optimal design of an intermediate elastic support with the minimum stiffness for the purpose of raising the fundamental frequency of the beam to a given value or to its upper bound. Based on the optimality criterion of the support design, the characteristic frequency equation can readily be formulated. Then, a closed-form solution is presented for estimating the minimum stiffness and optimum position of the intermediate support such that the analysis of the various classical boundary conditions is only a degenerate case of the present problem. With the procedure developed, the effects of the general cases of the beam restraint boundaries on the optimal design of the intermediate support are studied in detail. Numerical results show that the optimum position will move gradually apart from the end with the degree increment of the boundary restraints. Moreover, it is also observed that the rotational restraint affects the optimal design of the support more remarkably than the translational one at the lower values of the restraint constants, but becomes less effective at the higher constants.
Effects of Suction and Blowing on Flow and Heat Transfer Between Two Rotating Spheres With Time-Dependent Angular Velocities
Authors: Mahian Omid , Rahimi Asgahr B. , Jabari Moghadam Ali
Published: April 2011

The effect of suction and blowing in the study of flow and heat transfer of a viscous incompressible fluid between two vertically eccentric rotating spheres is presented when the spheres are maintained at different temperatures and rotating about a common axis while the angular velocities of the spheres are arbitrary functions of time. The resulting flow pattern, temperature distribution, and heat transfer characteristics are presented for the various cases including exponential and sinusoidal angular velocities. These presentations are for various values of the flow parameters including rotational Reynolds number Re, and the blowing/suction Reynolds number Rew. The effects of transpiration and eccentricity on viscous torques at the inner and outer spheres are studied, too. As the eccentricity increases and the gap between the spheres decreases the viscous torque remains nearly unchanged. Results for special case of concentric spheres are obtained by letting eccentricity tend to zero.
Effect of Increasing Number of Residential SOFC Cogeneration Systems Involved in Power Interchange Operation in Housing Complex on Energy Saving
Authors: Wakui Tetsuya , Yokoyama Ryohei
Published: March 2011

Residential solid oxide fuel cell cogeneration systems (R-FCGSs) have high generating efficiencies; however, they must be operated continuously because of their long warm-up times. Moreover, a reverse power flow from a residential cogeneration system to a commercial electric power system is not permitted in Japan. Because of these restrictions, it is considered that the R-FCGSs may not fully achieve their potential energy-saving effects in Japan. In order to improve the energy-saving effect of the R-FCGSs, the authors have been focusing on a power interchange operation using multiple R-FCGSs (IC) installed at residences in a housing complex as an application of a microgrid. In this operation, the electric power generated by the R-FCGSs is shared among the residences in the housing complex with no reverse power flow so that the electric load factor of the R-FCGSs may increase. This paper discusses the effect of increasing the number of the R-FCGSs involved in the IC on energy saving by conducting optimal operational planning based on mixed-integer linear programming. The numerical analyses for various numbers of target R-FCGSs, with a maximum of 20, clarify that the energy-saving effect of introducing the IC is not correlated with increasing the number of target R-FCGSs, but generally dominated by the total heat to power demand ratio and hourly variations in the electric power demand of the residences. Furthermore, it is revealed that for any number of target R-FCGSs, the IC has an advantage in the energy saving over a stand-alone operation of individual R-FCGSs without the power interchange.
A Gray-Box Based Virtual SCFM Meter in Rooftop Air-Conditioning Units
Authors: Yu Daihong , Li Haorong , Yu Yuebin
Published: April 2011

Knowledge of supply airflow rate (SCFM) measurement in packaged rooftop air-conditioning units (RTUs) is vital for improving energy management and indoor air quality and facilitating real-time automated control and fault detection and diagnosis. Despite the importance of SCFM measurement in RTUs, the conventional SCFM metering devices are very vulnerable. The credibility of SCFM measurement would be compromised dramatically after a long-term use in adverse duct work surroundings. Moreover, application of conventional SCFM meters in RTUs is very costly in regard to procurement, installation, and periodic maintenance. A cost-effective and accurate nonconventional first principles based SCFM meter in RTUs was proposed previously to virtually monitor SCFM measurement. In order to overcome the deficiencies of the first principles based virtual SCFM meter in model implementation and fault diagnostics, experiments with a wider combination and coverage are investigated in this study. It is found that a gray-box based virtual SCFM meter can be obtained with available system information (outside air damper status) and low-cost temperature measurements (direct measurement of a manufacturer-installed supply air temperature sensor (SATmfr,meas) and outside air temperature). Further experiment evaluations demonstrate that the gray-box based virtual SCFM meter could predict the true value of SCFM very accurately (the uncertainty is ±5.9%) with significantly enhanced applicability in model implementation and capability in fault diagnostics. Additionally, the gray-box based virtual SCFM meter also inherits good characteristics of the first principles based virtual SCFM meter, such as high cost-effectiveness, good robustness against variations in multivariable operating conditions, and applicability to similar RTUs. This innovative virtual meter could serve as a permanent monitoring tool to indicate real-time SCFM measurement and/or to automatically detect and diagnose an improper quantity of SCFM for RTUs.
Assisted hepatic resection using a toroidal HIFU device: An in vivo comparative study in pig
Authors: N'Djin W. A. , Melodelima D. , Schenone F. , Rivoire M. , Chapelon J. Y.
Published: April 2011

Purpose:

Bleeding is the main cause of postoperative complications during hepatic surgery. Blood loss and transfusions increase tumor recurrence in liver metastases from colorectal cancer. A high intensity focused ultrasound (HIFU) device with an integrated ultrasound imaging probe was developed for the treatment of colorectal liver metastasis.

Methods:

The HIFU toroidal‐shaped transducer contains 256 elements (working frequency: 3 MHz) and can create a single conical lesion of in 40 s. Then, the volume of treatment can be significantly increased by juxtaposing single lesions. Presented here is the use of this device in an animal model as a complementary tool to improve surgical resection in the liver. Before transecting the liver, a wall of coagulative necrosis was performed using this device in order to minimize blood loss and dissection time during hepatectomy. Resection assisted by HIFU was compared to classical dissections with clamping [intermittent Pringle maneuver (IPM) group] and without clamping (control group). For each technique, 14 partial liver resections were performed in seven pigs. Blood loss per dissection surface area and resection time were the main outcome parameters.

Results:

Conserving liver blood inflow during hepatic resection assisted by HIFU did not increase total blood loss compared to hepatic resection performed during IPM and controlled blood inflow . Lower blood loss was measured on average when using HIFU, even though difference with clamping (IPM) was not statistically significant . Resection assisted by HIFU reduced blood loss by 50% compared to control group (, ). The duration of transection when using HIFU was significantly lower compared to clamping (, ) and control (, ). Precoagulation also resulted in sealing blood vessels with a diameter of less than 5 mm, and therefore the number of clips needed in the HIFU group was significantly lower when compared to clamping (, ) and control (, ).

Conclusions:

This method holds promise for future clinical applications in resection of liver metastases.
Characterization and identification of spatial artifacts during 4D‐CT imaging
Authors: Han Dongfeng , Bayouth John , Bhatia Sudershan , Sonka Milan , Wu Xiaodong
Published: April 2011

Purpose:

The purpose of this work is twofold: First, to characterize the artifacts occurring in helical 4D‐CT imaging; second, to propose a method that canautomatically identify the artifacts in 4D‐CT images. The authors have designed a process that can automatically identify the artifacts in 4D‐CT images, which may be invaluable in quantifying the quality of 4D‐CT images and reducing the artifacts from the reconstructed images on a large dataset.

Methods:

Given two adjacent stacks obtained from the same respiration phase, the authors determine if there are artifacts between them. The proposed method uses a “bridge” stack strategy to connect the two stacks. Using normalized cross correlation convolution (NCCC), the two stacks are mapped to the bridge stack and the best matching positions can be located. Using this position information, the authors can then determine if there are artifacts between the two stacks. By combining the matching positions with NCCC values, the performance can be improved.

Results:

To validate the method, three expert observers independently labeled over 600 stacks on five patients. The results confirmed that high performance was obtained using the proposed method. The average sensitivity was about 0.87 and the average specificity was 0.82. The proposed method also outperformed the method of using respiratory signal (sensitivity increased from 0.50 to 0.87 and specificity increased from 0.70 to 0.82).

Conclusions:

This study shows that the spatial artifacts during 4D‐CT imaging are characterized and can be located automatically by the proposed method. The method is relatively simple but effective. It provides a way to evaluate the artifacts more objectively and accurately. The reported approach has promising potential for automatically identifying the types and frequency of artifacts on large scale 4D‐CT image dataset.
Deformable planning CT to cone‐beam CT image registration in head‐and‐neck cancer
Authors: Hou Jidong , Guerrero Mariana , Chen Wenjuan , D'Souza Warren D.
Published: April 2011

Purpose:

The purpose of this work was to implement and validate a deformable CT to cone‐beam computed tomography (CBCT) image registration method in head‐and‐neck cancer to eventually facilitate automatic target delineation on CBCT.

Methods:

Twelve head‐and‐neck cancer patients underwent a planning CT and weekly CBCT during the 5–7 week treatment period. The 12 planning CT images (moving images) of these patients were registered to their weekly CBCT images (fixed images) via the symmetric force Demons algorithm and using a multiresolution scheme. Histogram matching was used to compensate for the intensity difference between the two types of images. Using nine known anatomic points as registration targets, the accuracy of the registration was evaluated using the target registration error (TRE). In addition, region‐of‐interest (ROI) contours drawn on the planning CT were morphed to the CBCT images and the volume overlap index (VOI) between registered contours and manually delineated contours was evaluated.

Results:

The mean TRE value of the nine target points was less than 3.0 mm, the slice thickness of the planning CT. Of the 369 target points evaluated for registration accuracy, the average TRE value was . The mean TRE for bony tissue targets was , while the mean TRE for soft tissue targets was . The average VOI between the registered and manually delineated ROI contours was , which is consistent with that reported in previous studies.

Conclusions:

The authors have implemented and validated a deformable image registration method to register planning CT images to weekly CBCT images in head‐and‐neck cancer cases. The accuracy of the TRE values suggests that they can be used as a promising tool for automatic target delineation on CBCT.
Demons deformable registration of CT and cone‐beam CT using an iterative intensity matching approach
Authors: Nithiananthan Sajendra , Schafer Sebastian , Uneri Ali , Mirota Daniel J. , Stayman J. Webster , Zbijewski Wojciech , Brock Kristy K. , Daly Michael J. , Chan Harley , Irish Jonathan C. , Siewerdsen Jeffrey H.
Published: April 2011

Purpose:

A method of intensity‐based deformable registration of CT and cone‐beam CT (CBCT) images is described, in which intensity correction occurs simultaneously within the iterative registration process. The method preserves the speed and simplicity of the popular Demons algorithm while providing robustness and accuracy in the presence of large mismatch between CT and CBCT voxel values (“intensity”).

Methods:

A variant of the Demons algorithm was developed in which an estimate of the relationship between CT and CBCT intensity values for specific materials in the image is computed at each iteration based on the set of currently overlapping voxels. This tissue‐specific intensity correction is then used to estimate the registration output for that iteration and the process is repeated. The robustness of the method was tested in CBCT images of a cadaveric head exhibiting a broad range of simulated intensity variations associated with x‐ray scatter, object truncation, and/or errors in the reconstruction algorithm. The accuracy of CT‐CBCT registration was also measured in six real cases, exhibiting deformations ranging from simple to complex during surgery or radiotherapy guided by a CBCT‐capable C‐arm or linear accelerator, respectively.

Results:

The iterative intensity matching approach was robust against all levels of intensity variation examined, including spatially varying errors in voxel value of a factor of 2 or more, as can be encountered in cases of high x‐ray scatter. Registration accuracy without intensity matching degraded severely with increasing magnitude of intensity error and introduced image distortion. A single histogram match performed prior to registration alleviated some of these effects but was also prone to image distortion and was quantifiably less robust and accurate than the iterative approach. Within the six case registration accuracy study, iterative intensity matching Demons reduced mean TRE to compared to with rigid registration.

Conclusions:

A method was developed to iteratively correct CT‐CBCT intensity disparity during Demons registration, enabling fast, intensity‐based registration in CBCT‐guided procedures such as surgery and radiotherapy, in which CBCT voxel values may be inaccurate. Accurate CT‐CBCT registration in turn facilitates registration of multimodality preoperative image and planning data to intraoperative CBCT by way of the preoperative CT, thereby linking the intraoperative frame of reference to a wealth of preoperative information that could improve interventional guidance.
Proton radiography and fluoroscopy of lung tumors: A Monte Carlo study using patient‐specific 4DCT phantoms
Authors: Han Bin , Xu X. George , Chen George T. Y.
Published: April 2011

Purpose:

Monte Carlo methods are used to simulate and optimize a time‐resolved proton range telescope (TRRT) in localization of intrafractional and interfractional motions of lung tumor and in quantification of proton range variations.

Methods:

The Monte Carlo N‐Particle eXtended (MCNPX) code with a particle tracking feature was employed to evaluate the TRRT performance, especially in visualizing and quantifying proton range variations during respiration. Protons of 230 MeV were tracked one by one as they pass through position detectors, patient 4DCT phantom, and finally scintillator detectors that measured residual ranges. The energy response of the scintillator telescope was investigated. Mass density and elemental composition of tissues were defined for 4DCT data.

Results:

Proton water equivalent length (WEL) was deduced by a reconstruction algorithm that incorporates linear proton track and lateral spatial discrimination to improve the image quality. 4DCT data for three patients were used to visualize and measure tumor motion and WEL variations. The tumor trajectories extracted from the WEL map were found to be within agreement with direct 4DCT measurement. Quantitative WEL variation studies showed that the proton radiograph is a good representation of WEL changes from entrance to distal of the target.

Conclusions:

MCNPX simulation results showed that TRRT can accurately track the motion of the tumor and detect the WEL variations. Image quality was optimized by choosing proton energy, testing parameters of image reconstruction algorithm, and comparing to ground truth 4DCT. The future study will demonstrate the feasibility of using the time resolved proton radiography as an imaging tool for proton treatments of lung tumors.
Dynamic gating window for compensation of baseline shift in respiratory‐gated radiation therapy
Authors: Pepin Eric W. , Wu Huanmei , Shirato Hiroki
Published: April 2011

Purpose:

To analyze and evaluate the necessity and use of dynamic gating techniques for compensation of baseline shift during respiratory‐gated radiation therapy of lung tumors.

Methods:

Motion tracking data from 30 lung tumors over 592 treatment fractions were analyzed for baseline shift. The finite state model (FSM) was used to identify the end‐of‐exhale (EOE) breathing phase throughout each treatment fraction. Using duty cycle as an evaluation metric, several methods of end‐of‐exhale dynamic gating were compared: Ana posteriori ideal gating window, a predictive trend‐line‐based gating window, and a predictive weighted point‐based gating window. These methods were evaluated for each of several gating window types: Superior/inferior (SI) gating, anterior/posterior beam, lateral beam, and 3D gating.

Results:

In the absence of dynamic gating techniques, SI gating gave a 39.6% duty cycle. The ideal SI gating window yielded a 41.5% duty cycle. The weight‐based method of dynamic SI gating yielded a duty cycle of 36.2%. The trend‐line‐based method yielded a duty cycle of 34.0%.

Conclusions:

Dynamic gating was not broadly beneficial due to a breakdown of the FSM's ability to identify the EOE phase. When the EOE phase was well defined, dynamic gating showed an improvement over static‐window gating.
Local and global 3D noise power spectrum in cone‐beam CT system with FDK reconstruction
Authors: Baek Jongduk , Pelc Norbert J.
Published: April 2011

Purpose:

The authors examine the nonstationary noise behavior of a cone‐beam CT system with FDK reconstruction.

Methods:

To investigate the nonstationary noise behavior, an analytical expression for the NPS of local volumes and an entire volume was derived and quantitatively compared to the NPS estimated from experimental air and water images.

Results:

The NPS of local volumes at different locations along the‐axis showed radial symmetry in theplane and different missing cone regions in thedirection depending on the tilt angle of rays through the local volumes. For local volumes away from the‐axis, the NPS of air and water images showed sharp transitions in theandplanes and lack of radial symmetry in theplane. These effects are mainly caused by varying magnification and different noise levels from view to view. In the NPS of the entire volume, theplane showed radial symmetry because the nonstationary noise behaviors of local volumes were averaged out. The nonstationary sharp transitions were manifested as a high‐frequency roll‐off.

Conclusions:

The results from noise power analysis for local volumes and an entire volume demonstrate the spatially varying noise behavior in the reconstructed cone‐beam CT images.
Calibration of GafChromic XR‐RV3 radiochromic film for skin dose measurement using standardized x‐ray spectra and a commercial flatbed scanner
Authors: McCabe Bradley P. , Speidel Michael A. , Pike Tina L. , Van Lysel Michael S.
Published: April 2011

Purpose:

In this study, newly formulated XR‐RV3 GafChromic® film was calibrated with National Institute of Standards and Technology (NIST) traceability for measurement of patient skin dose during fluoroscopically guided interventional procedures.

Methods:

The film was calibrated free‐in‐air to air kerma levels between 15 and 1100 cGy using four moderately filtered x‐ray beam qualities (60, 80, 100, and 120 kVp). The calibration films were scanned with a commercial flatbed document scanner. Film reflective density‐to‐air kerma calibration curves were constructed for each beam quality, with both the orange and white sides facing the x‐ray source. A method to correct for nonuniformity in scanner response (up to 25% depending on position) was developed to enable dose measurement with large films. The response of XR‐RV3 film under patient backscattering conditions was examined using on‐phantom film exposures and Monte Carlo simulations.

Results:

The response of XR‐RV3 film to a given air kerma depended on kVp and film orientation. For a 200 cGy air kerma exposure with the orange side of the film facing the source, the film response increased by 20% from 60 to 120 kVp. At 500 cGy, the increase was 12%. When 500 cGy exposures were performed with the white side facing the x‐ray source, the film response increased by 4.0% (60 kVp) to 9.9% (120 kVp) compared to the orange‐facing orientation. On‐phantom film measurements and Monte Carlo simulations show that using a NIST‐traceable free‐in‐air calibration curve to determine air kerma in the presence of backscatter results in an error from 2% up to 8% depending on beam quality. The combined uncertainty in the air kerma measurement from the calibration curves and scanner nonuniformity correction was ±7.1% (95% C.I.). The film showed notable stability. Calibrations of film and scanner separated by 1 yr differed by 1.0%.

Conclusions:

XR‐RV3 radiochromic film response to a given air kerma shows dependence on beam quality and film orientation. The presence of backscatter slightly modifies the x‐ray energy spectrum; however, the increase in film response can be attributed primarily to the increase in total photon fluence at the sensitive layer. Film calibration curves created under free‐in‐air conditions may be used to measure dose from fluoroscopic quality x‐ray beams, including patient backscatter with an error less than the uncertainty of the calibration in most cases.