bluuebunny/crossref_metadata_2025 huggingface dataset:
The cost‐effectiveness of sibutramine in non‐diabetic obese patients: evidence from four Western countries
Authors: Ara R. , Brennan A.
Published: February 2007

This paper aims to assess the cost‐effectiveness of sibutramine in treating obese patients in the Western countries. The model estimates the costs and quality of life benefits directly associated with weight losses combined with the costs and benefits associated with the reduced incidence of coronary heart disease (CHD) and diabetes. The pivotal effectiveness evidence is derived from a German multicentre, double‐blind, randomized clinical trial on obese (body mass index ≥ €30 kg m−2) patients. The incremental cost per quality‐adjusted life year ranges from €10 734 in Switzerland to €13 707 in Germany. The total number of CHD events avoided ranges from 1.96 for the UK to 4.49 for Switzerland. The number of diabetes cases avoided is in the region of 3.0 (ranges from 2.58 for Germany to 3.28 for Switzerland). The majority of costs and benefits are accrued through sibutramine treatment and monitoring. Univariate sensitivity analyses show that results are sensitive to changes in the utility directly attributable to weight losses. The results demonstrate that the benefits associated with sibutramine‐induced weight losses are obtained at a reasonable cost in each of the settings explored and suggest that sibutramine treatment could be considered as a viable option for pharmacotherapy treatment alongside diet and exercise.
MEASURING INEQUALITY TRENDS IN COLONIAL AUSTRALIA USING FACTOR–PRICE RATIOS: THE IMPORTANCE OF BOUNDARIES
Authors: Shanahan Martin P. , Wilson John K.
Published: February 2007

Previous research on nineteenth century globalisation argues that during the second half of that century wage–rental ratios in labour scarce, land‐abundant new world economies decreased. This suggests inequality rose in the new world. Australia has been cited as a conspicuous example of this trend. The paper re‐examines this argument using disaggregated land and wage data for four Australian colonies. We reveal large regional differences in both factor–price levels and trends – something that has been overlooked when discussing Australian colonial inequality and we suggest that regional disparities in other nineteenth century economies are also likely to be important.
THE SWEDISH WAGE–RENTAL RATIO AND ITS DETERMINANTS, 1877–1926
Authors: Bohlin Jan , Larsson Svante
Published: February 2007

Trends in wage–rental ratios figure prominently in the recent literature on factor price convergence and globalisation in the late nineteenth century. Sweden has been described as a free‐trade country whose wage–rental ratio exhibited a distinctive upward trend before World War I. This article presents a new land price series that indicates an increase in land rentals and an evolution of the wage–rental ratio more in line with other European protectionist countries. We explore the determinants of the Swedish wage–rental ratio and assess the relative importance of protectionism and changes in Swedish farming’s product mix from crop to animal products.
LABOUR AND LAND IN GHANA, 1874–1939: A SHIFTING RATIO AND AN INSTITUTIONAL REVOLUTION
Authors: Austin Gareth
Published: February 2007

The Second Industrial Revolution created markets for new products for Ghana, rubber and then cocoa beans. Mechanised transport spurred the spread of cocoa planting. The paper estimates the resultant shift in factor ratios, and synthesises the data for prices of land‐use rights and wages as the economy moved from land abundance to localised land scarcity. The consequences for factor markets were institutional rather than simply quantitative. For the first time markets in land use rights became widespread, while hired labour and farm pledging replaced slavery and debt bondage, as cocoa income made it possible for farmers to offer labourers sufficient inducement to enter the labour market.
THE FUTURE TRAJECTORY OF U.S. CO2 EMISSIONS: THE ROLE OF STATE VS. AGGREGATE INFORMATION*
Authors: Auffhammer Maximilian , Steinhauser Ralf
Published: February 2007

ABSTRACT This paper provides comparisons of a variety of time‐series methods for short‐run forecasts of the main greenhouse gas, carbon dioxide, for the United States, using a recently released state‐level data set from 1960–2001. We test the out‐of‐sample performance of univariate and multivariate forecasting models by aggregating state‐level forecasts versus forecasting the aggregate directly. We find evidence that forecasting the disaggregate series and accounting for spatial effects drastically improves forecasting performance under root mean squared forecast error loss. Based on the in‐sample observations we attempt to explain the emergence of voluntary efforts by states to reduce greenhouse gas emissions. We find evidence that states with decreasing per capita emissions and a “greener” median voter are more likely to push toward voluntary cutbacks in emissions.
WET GROWTH: EFFECTS OF WATER POLICIES ON LAND USE IN THE AMERICAN WEST*
Authors: Hanak Ellen , Chen Ada
Published: February 2007

ABSTRACT Rapid population growth and increasing water development costs have prompted many western governments to condition residential development approval on the adequacy of water supplies. We examine the effects of these regulations on housing supply in Colorado and New Mexico using fixed‐effects panel regressions. Our findings suggest that price‐based tools to ensure water availability may be a preferred regulatory alternative to quantity restrictions. Attempts to restrict groundwater basin access have not unambiguously corrected negative externalities related to growth. Meanwhile, Colorado cities' aggressive use of impact fees has facilitated water resource development, without limiting growth.
REGULATORY FEDERALISM AND THE DISTRIBUTION OF AIR POLLUTANT EMISSIONS*
Authors: Bulte Erwin , List John A. , Strazicich Mark C.
Published: February 2007

ABSTRACT Recent empirical work suggests that (i) incomes are converging through time, and (ii) income and pollution levels are linked. This paper weds these two literatures by examining the spatial and temporal distribution of pollution. After establishing that theoretical predictions about whether pollution will converge are critically linked to certain structural parameters, we explore pollution convergence using state‐level data on two important pollutants—nitrogen oxides and sulfur oxides—from 1929 to 1999. We find stronger evidence of converging emission rates during the federal pollution control years (1970–1999) than during the local control years (1929–1969). These results suggest that income convergence alone may not be sufficient to induce convergence of pollutant emissions.
Striatal dopamine transporter binding in patients with Parkinson's disease and severe occupational hydrocarbon exposure
Authors: Canesi M. , Benti R. , Marotta G. , Cilia R. , Isaias I. U. , Gerundini P. , Pezzoli G. , Antonini A.
Published: February 2007

We used 123I‐Ioflupane SPECT to study striatal dopamine transporter (DAT) binding in 36 Parkinson's disease (PD) patients with history of severe occupational exposure to hydrocarbons. Data were compared with 38 PD patients without exposure history as well as healthy controls. Both PD cohorts showed significant striatal uptake decrements compared with controls. We found significantly lower values in the whole striatum of exposed compared with non‐exposed patients (0.83 ± 0.25 vs. 1.05 ± 0.39; P = 0.004), more pronounced in the putamen (0.61 ± 0.24 vs. 0.85 ± 0.42; P = 0.004). We conclude that severe occupational exposure to hydrocarbons may modify disease course and ultimately accelerate nigro‐striatal denervation.
Telangiectasia Macularis Eruptiva Perstans: Unusual Presentation and Treatment
Authors: Rishpon Ayelet , Matz Hagit , Gat Andrea , Brenner Sarah
Published: February 2007

A 41‐year‐old woman presented with a 2‐month history of pruritus and a generalized dermatitis that developed initially on the head and spread to the trunk, legs, and buttocks. The pruritus caused extreme discomfort and was not relieved by antihistamines or topical steroid treatment. The patient denied flushing, syncope, and vomiting. Her medical history included asthma treated with salmeterol/fluticasone propionate inhaler, and status post silicone breast augmentation. Physical examination revealed a papular dermatitis on the trunk and extremities composed of lesions up to O.S cm in diameter, surrounded by excoriation marks (Figure 1). There was no hepatosplenomegaly or lymphadenopathy. Darier's sign was negative. Results of complete blood count, peripheral blood film examination, and liver function tests were all with normal limits. A biopsy specimen taken from a lesion and stained with hematoxylin‐eosin showed telangiectasias, with an increased number of mast cells around blood vessels (Figure 2). Positive Giemsa (Figure 3) and c‐kit stain (Figure 4) indicated an increased number of mast cells. Bone marrow aspiration and total body CT performed to rule out systemic involvement showed no pathology. Protein electrophoresis was normal. Serum tryptase and histamine were within normal limits, and 24‐hour urine collection for histamine was normal. Narrow‐band UV‐B treatment was begun 3 times weekly, reduced to twice weekly after 2 months, and then stopped. The first few treatments resulted in significant relief of the pruritus and regression of lesions. After 3 months without treatment, the patient remained free of pruritus and lesions.

Patient before treatment; skin showing papular dermatitis and excoriation marks.

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Skin specimen showing telangiectasias and moderately dense perivascular infiltrate composed of lymphocytes, eosinophils, and mast cells (hematoxylineosin stain; original magnification ×10).

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Giemsa stain highlighting cytoplasmic mast cell granules (original magnification ×40).

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C‐kit (CD117) stain highlighting mast cells (original magnification ×20).

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Bite the Hand That Sprays You
Authors: Ismailjee Sameer B. , Bernstein Jack M. , Burdette Steven D.
Published: February 2007

A 56‐year‐old man presented with a cutaneous lesion on his right hand (Figure 1). Approximately 6 weeks previously, he had traveled to Costa Rica for missionary work. During his travel he used a diethyltoluamide‐containing insect repellant, but spent one night in the jungle without a mosquito net. Four weeks after his return, he noted a 3 × 2.5‐cm ulcer with raised edges and surrounding erythema on the dorsum of his right hand. The patient recalled applying insect repellant with his right hand to other exposed areas of his body but was remiss in applying it to the right hand itself. On examination, the patient was noted to have an ulcerated nodule near his right earlobe (Figure 2) and a second 2 × 1‐cm ulcer on the volar aspect of his right wrist (Figure 3). There were no mucocutaneous lesions noted. During the next several weeks, numerous nodules developed in a sporotrichoid pattern on the extensor surface of his right arm (Figure 4). Skin biopsy was performed at the time of initial evaluation and revealed cutaneous leishmaniasis due to Leishmania panamensis. After discussing the different treatment options, miltefosine was administered orally for 28 days. The patient experienced an excellent response to therapy.

Ulcer, dorsum, right hand.

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Eschar, anterior to right ear.

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Ulcer, volar surface, right forearm.

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Sporotrichoid lesions, right forearm.

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Hyaluronic Acid for Restoring Earlobe Volume
Authors: de Oliveira Monteiro Erica
Published: February 2007

Cosmetic disfigurement of the earlobe, including laxity and sagging skin, comes with aging. Restoring the earlobe volume is a procedure indicated for patients seeking a youthful facial appearance. Hyaluronic acid is a good choice for this procedure. Most fillers on the market today are supplied with a small needle, yet a larger‐gauge needle allows the introduction of the product under lower pressure, making it easier and faster to fill tight areas. This article describes a useful approach to enhance the hyaluronic acid injection, resulting in a fast and effective method to restore earlobe volume.
Perinuclear Antineutrophil Cytoplasmic Antibody‐Associated Vasculitis in a Patient With Graves' Disease Treated With Methimazole
Authors: Martin Donna Bilu , Deng April , Gaspari Anthony , Pearson Frederick
Published: February 2007

A 15‐year‐old Caucasian girl presented with a 1‐week history of necrotic ulcers on her bilateral lower extremities, associated with fever and malaise. She had had similar ulcerations on and off over the past 3 years. She had a medical history of Graves' disease, diagnosed in 1999, for which she was taking methimazole (MMI). On physical examination, there were multiple necrotic ulcers with elevated, inflamed borders and an overlying eschar on the bilateral distal extremities (Figure 1). There was one hemorrhagic, flaccid bulla on the lateral aspect of the ankle. Her complete blood count, comprehensive metabolic panel, prothrombin time, and international normalized ratio were within normal limits. Histopathology revealed a neutrophilic vasculitis involving small as well as medium‐sized blood vessels. The overlying epidermis and upper dermis showed necrosis (Figure 2). Antinuclear antibody (ANA) was positive at 1:160. Perinuclear (p‐) antineutrophil cytoplasmic antibody (ANCA) was positive at 1:320. Cytoplasmic ANCA was negative. The patient did not meet any clinical criteria for a diagnosis of lupus erythematosus. Direct immunofluorescence revealed IgM, complement C3, and fibrin in small‐ and medium‐caliber blood vessels in the dermis, consistent with a leukocytoclastic vasculitis of small‐ and medium‐caliber blood vessels (Figure 3). MMI was stopped and the patient was given prednisone, tapered over 5 days. Her thyroid function remained stable, and she did not develop new necrotic ulcers. One month later, the patient developed urticarial lesions on her lower extremities. Histopathology revealed a lymphocytic vascular reaction. No eosinophils or neutrophils were seen. These newer urticarial lesions resolved. The patient underwent debridement of the thick, necrotic ulcerative eschars. To date, her lesions have resolved (Figure 4). An ANA drawn S months after withdrawal of MMI was negative, and p‐ANCA was 1:67.

On initial physical examination, there were multiple necrotic ulcers with elevated, inflamed borders and an overlying eschar on the bilateral distal extremities.

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Neutrophilic vasculitis involving small as well as medium‐sized blood vessels. The overlying epidermis and upper dermis showed necrosis and dermolysis. There is necrosis in the vessels. Hematoxylin and eosin stain; original magnification ×7 00.

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Direct immuno‐fluorescence revealed IgM, complement C3, and fibrin in small‐ and medium‐caliber blood vessels in the dermis, consistent with a leukocytoclastic vasculitis of small‐ and medium‐caliber blood vessels. Fluorescein‐conjugated goat antihuman IgM stain; original magnification ×200.

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On 5‐month follow‐up, the ulcers have nearly completely healed.

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Botulinum Toxin and Pregnancy
Authors: de Oliveira Monteiro Erica
Published: February 2007

The overall use of botulinum toxin type A in cosmetic procedures continues to rise, and the incidental exposures of pregnant women to the drug can occur. The author describes 2 patients who received botulinum toxin type A injections during pregnancy. The first patient was a 34‐year‐old woman who received 54 units of botulinum toxin type A to treat periorbital lines (crow's feet) unaware that she was 6 weeks pregnant. She had a healthy term baby delivered by cesarean section; Apgar scores were 9/10. The second patient was a 37‐year‐old woman who received 65 units of botulinum toxin type A to treat facial dynamic lines (forehead, glabelar, and periorbital), unaware that she was 5 weeks pregnant. She had a healthy term baby delivered by cesarean section; Apgar scores were 9/10. The 2 patients were injected only once in the first trimester. Both cases did not have any complications or detectable adverse effects on the fetuses.
Mitogen‐activated protein kinases mediate interleukin‐1β‐induced receptor activator of nuclear factor‐κB ligand expression in human periodontal ligament cells
Authors: Oikawa A. , Kobayashi M. , Okamatsu Y. , Shinki T. , Kamijo R. , Yamamoto M. , Hasegawa K.
Published: February 2007

Background and Objective:  Interleukin‐1β‐stimulated receptor activator of nuclear factor‐κB ligand (RANKL) expression in human periodontal ligament cells is partially mediated by endogenous prostaglandin E2, whereas mitogen‐activated protein kinases (MAPKs) are implicated in regulating various interleukin‐1‐responsive genes. We investigated herein the involvement of MAPKs in interleukin‐1β‐stimulated RANKL expression in human periodontal ligament cells.

Material and Methods:  Human periodontal ligament cells were pretreated separately with specific inhibitors of MAPKs, including extracellular signal‐regulated kinase, p38 MAPK and c‐Jun N‐terminal kinase, and subsequently treated with interleukin‐1β. Following each treatment, the phosphorylation of each MAPK, the expression of RANKL, and the production of prostaglandin E2 were determined. RANKL activity was evaluated using an assay to determine the survival of prefusion osteoclasts.

Results:  Interleukin‐1β induced RANKL expression at the mRNA and protein levels, as well as RANKL activity in human periodontal ligament cells. Interleukin‐1β also activated extracellular signal‐regulated kinase, p38 MAPK, and c‐Jun N‐terminal kinase. Pretreatment with each MAPK inhibitor partially, but significantly, suppressed interleukin‐1β‐induced RANKL expression and its activity, as well as prostaglandin E2 production.

Conclusion:  In human periodontal ligament cells, three types of MAPK inhibitor may abrogate RANKL expression and activity induced by interleukin‐1β, directly or indirectly through partial suppression of prostaglandin E2 synthesis. In addition, extracellular signal‐regulated kinase, p38 MAPK, and c‐Jun N‐terminal kinase signals may co‐operatively mediate interleukin‐1β‐stimulated RANKL expression and its activity in those cells.
WHY “WHAT WORKS” WON’T WORK: EVIDENCE‐BASED PRACTICE AND THE DEMOCRATIC DEFICIT IN EDUCATIONAL RESEARCH
Authors: Biesta Gert
Published: February 2007

Abstract In this essay, Gert Biesta provides a critical analysis of the idea of evidence‐based practice and the ways in which it has been promoted and implemented in the field of education, focusing on the tension between scientific and democratic control over educational practice and research. Biesta examines three key assumptions of evidence‐based education: first, the extent to which educational practice can be compared to the practice of medicine, the field in which evidence‐based practice was first developed; second, the role of knowledge in professional actions, with special attention to what kind of epistemology is appropriate for professional practices that wish to be informed by the outcomes of research; and third, the expectations about the practical role of research implicit in the idea of evidence‐based education. Biesta concludes that evidence‐based practice provides a framework for understanding the role of research in educational practice that not only restricts the scope of decision making to questions about effectivity and effectiveness, but that also restricts the opportunities for participation in educational decision making. He argues that we must expand our views about the interrelations among research, policy, and practice to keep in view education as a thoroughly moral and political practice that requires continuous democratic contestation and deliberation.
The Law: Presidential Inherent Power: The “Sole Organ” Doctrine
Authors: FISHER LOUIS
Published: February 2007

The executive branch relies in part on the “sole organ” doctrine to define presidential power broadly in foreign relations and national security, including assertions of an inherent executive power that is not subject to legislative or judicial constraints. The doctrine draws from a statement by John Marshall as a member of the House of Representatives in 1800: “The President is the sole organ of the nation in its external relations, and its sole representative with foreign nations.” In dicta, the Supreme Court, in United States v. Curtiss‐Wright (1936), cited Marshall's speech to support an independent, extra‐constitutional, or exclusive power of the president. When read in context, however, Marshall made no such claim.
REGIONAL TIES AND DISCRIMINATION: POLITICAL CHANGE, ECONOMIC CRISIS, AND JOB DISPLACEMENTS IN SOUTH KOREA, 1997–99
Authors: KANG Changhui , LEE Seungjoo
Published: February 2007

Probing into the incidence of job displacements during the 1997–99 recession period, this study offers theoretically grounded micro‐causal explanations for regional ties and regional discrimination in South Korea. Our statistical analysis reveals the significant impact of a worker's birth region (the basis of regional ties and discrimination) on the layoff process. Native Kyongsang workers are found to have faced higher rates of layoff in Seoul‐Kyongki regional firms than native Jolla workers during the recession period. The Kyongsang–Jolla layoff rate gap is mainly due to differential treatment rather than a difference in observable characteristics. The findings suggest that the problem of regional ties and regional discrimination is more deep‐rooted and widespread in South Korea than previously reported.
Characterization, prediction, and correction of geometric distortion in MR images
Authors: Baldwin Lesley N. , Wachowicz Keith , Thomas Steven D. , Rivest Ryan , Fallone B. Gino
Published: February 2007

The work presented herein describes our methods and results for predicting, measuring and correcting geometric distortions in a clinical magnetic resonance (MR) scanner for the purpose of image guidance in radiation treatment planning. Geometric inaccuracies due to both inhomogeneities in the background field and nonlinearities in the applied gradients were easily visualized on the MR images of a regularly structured three‐dimensional (3D) grid phantom. From a computed tomography scan, the locations of just under control points within the phantom were accurately determined in three dimensions using a MATLAB‐based computer program. MR distortion was then determined by measuring the corresponding locations of the control points when the phantom was imaged using the MR scanner. Using a reversed gradient method, distortions due to gradient nonlinearities were separated from distortions due to inhomogeneities in the background field. Because the various sources of machine‐related distortions can be individually characterized, distortions present in other imaging sequences (for which 3D distortion cannot accurately be measured using phantom methods) can be predicted negating the need for individual distortion calculation for a variety of other imaging sequences. Distortions were found to be primarily caused by gradient nonlinearities and maximum image distortions were reported to be less than those previously found by other researchers at . Finally, the image slices were corrected for distortion in order to provide geometrically accurate phantom images.
Three‐dimensional finite‐element‐based photoacoustic tomography: Reconstruction algorithm and simulations
Authors: Yuan Zhen , Jiang Huabei
Published: February 2007

In this paper, a finite element reconstruction algorithm for three‐dimensional photoacoustic tomography is described. The algorithm is based on rigorous iterative solution to the Helmholtz photoacoustic wave equation coupled with regularization techniques and is able to recover both the images of absorbed optical energy density and acoustic speed simultaneously. The algorithm is tested using various numerical examples that mimic cancer detection and joint imaging. The results show that the algorithm is able to reconstruct photoacoustic images quantitatively in terms of the location, size, optical and acoustic properties of the target, and background media for various examples examined.
An arc‐sequencing algorithm for intensity modulated arc therapy
Authors: Shepard D. M. , Cao D. , Afghan M. K. N. , Earl M. A.
Published: February 2007

Intensity modulated arc therapy (IMAT) is an intensity modulated radiation therapy delivery technique originally proposed as an alternative to tomotherapy. IMAT uses a series of overlapping arcs to deliver optimized intensity patterns from each beam direction. The full potential of IMAT has gone largely unrealized due in part to a lack of robust and commercially available inverse planning tools. To address this, we have implemented an IMAT arc‐sequencing algorithm that translates optimized intensity maps into deliverable IMAT plans. The sequencing algorithm uses simulated annealing to simultaneously optimize the aperture shapes and weights throughout each arc. The sequencer enforces the delivery constraints while minimizing the discrepancies between the optimized and sequenced intensity maps. The performance of the algorithm has been tested for ten patient cases (3 prostate, 3 brain, 2 head‐and‐neck, 1 lung, and 1 pancreas). Seven coplanar IMAT plans were created using an average of 4.6 arcs and 685 monitor units. Additionally, three noncoplanar plans were created using an average of 16 arcs and 498 monitor units. The results demonstrate that the arc sequencer can provide efficient and highly conformal IMAT plans. An average sequencing time of approximately was observed.
Potential for dose‐escalation and reduction of risk in pancreatic cancer using IMRT optimization with lexicographic ordering and gEUD‐based cost functions
Authors: Spalding Aaron C. , Jee Kyung‐Wook , Vineberg Karen , Jablonowski Marla , Fraass Benedick A. , Pan Charlie C. , Lawrence Theodore S. , Ten Haken Randall K. , Ben‐Josef Edgar
Published: February 2007

Radiotherapy for pancreatic cancer is limited by the tolerance of local organs at risk (OARs) and frequent overlap of the planning target volume (PTV) and OAR volumes. Using lexicographic ordering (LO), a hierarchical optimization technique, with generalized equivalent uniform dose (gEUD) cost functions, we studied the potential of intensity modulated radiation therapy (IMRT) to increase the dose to pancreatic tumors and to areas of vascular involvement that preclude surgical resection [surgical boost volume (SBV)]. We compared 15 forward planned three‐dimensional conformal (3DCRT) and IMRT treatment plans for locally advanced unresectable pancreatic cancer. We created IMRT plans optimized using LO with gEUD‐based cost functions that account for the contribution of each part of the resulting inhomogeneous dose distribution. LO‐IMRT plans allowed substantial PTV dose escalation compared with 3DCRT; median increase from to and median increase from to . LO‐IMRT also allowed increases to in the SBV, regardless of value, along with significant dose reductions in OARs. We conclude that LO‐IMRT with gEUD cost functions could allow dose escalation in pancreas tumors with concomitant reduction in doses to organs at risk as compared with traditional 3DCRT.
Organ and effective doses in infants undergoing upper gastrointestinal (UGI) fluoroscopic examination
Authors: Staton Robert J. , Williams Jonathon L. , Arreola Manuel M. , Hintenlang David E. , Bolch Wesley E.
Published: February 2007

To provide more detailed data on organ and effective doses in digital upper gastrointestinal (UGI) fluoroscopy studies of newborns and infants, the present study was conducted employing the time‐sequence videotape‐analysis technique used in a companion study of newborn and infant voiding cystourethrograms (VCUG). This technique was originally pioneered [O. H. Suleiman, J. Anderson, B. Jones, G. U. Rao, and M. Rosenstein, Radiology 178, 653–658 (1991)] for adult UGI examinations. Individual video frames were analyzed to include combinations of field size, field center, x‐ray projection, image intensifier, and magnification mode. Additionally, the peak tube potential and the mA or mAs values for each segment/subsegment or digital photospot were recorded for both the fluoroscopic and radiographic modes of operation. The data from videotape analysis were then used in conjunction with a patient‐scalable newborn tomographic computational phantom to report both organ and effective dose values via Monte Carlo radiation transport. The study includes dose estimates for five simulated UGI examinations representative of patients ranging from three to six months of age. Effective dose values for UGI examinations ranged from 1.17 to , with a mean of and a large standard deviation of . The colon, lungs, stomach, liver, and esophagus absorbed doses in sum were found to constitute between 63 and 75% of the effective dose in these UGI studies. Representing 23–30% of the effective dose, the lungs were found to be the most significant organ in the effective dose calculation. Approximately 80–95% of the effective dose is contributed by the dynamic fluoroscopy segments with larger percentages found in longer studies. The mean effective dose for newborn UGI examinations was not found to be statistically different from that seen in newborn VCUG examinations.
High antinoise photoacoustic tomography based on a modified filtered backprojection algorithm with combination wavelet
Authors: Zeng Lvming , Xing Da , Gu Huaimin , Yang Diwu , Yang Sihua , Xiang Liangzhong
Published: February 2007

How to extract the weak photoacoustic signals from the collected signals with high noise is the key to photoacoustic signal processing. We have developed a modified filtered backprojection algorithm based on combination wavelet for high antinoise photoacoustic tomography. A –switched‐Nd: yttrium–aluminum–garnet laser operating at is used as light source. The laser has a pulse width of and a repetition frequency of . A needle polyvinylidene fluoride hydrophone with diameter of is used to capture photoacoustic signals. The modified algorithm is successfully applied to imaging vascular network of a chick embryo chorioallantoic membrane in situ and brain structure of a rat brain in vivo, respectively. In the reconstructed images, almost all of the capillary vessels and the vascular ramifications of the chick embryo chorioallantoic membrane are accurately resolved, and the detailed brain structures of the rat brain organization are clearly identified with the skull and scalp intact. The experimental results demonstrate that the modified algorithm has much higher antinoise capacity, and can greatly improve the reconstruction image quality. The spatial resolution of the reconstructed images can reach . The modified filtered backprojection algorithm based on the combination wavelet has the potential in the practical high‐noise signal processing for deeply penetrating photoacoustic tomography.
Scatter radiation in digital tomosynthesis of the breast
Authors: Sechopoulos Ioannis , Suryanarayanan Sankararaman , Vedantham Srinivasan , D'Orsi Carl J. , Karellas Andrew
Published: February 2007

Digital tomosynthesis of the breast is being investigated as one possible solution to the problem of tissue superposition present in planar mammography. This imaging technique presents various advantages that would make it a feasible replacement for planar mammography, among them similar, if not lower, radiation glandular dose to the breast; implementation on conventional digital mammography technology via relatively simple modifications; and fast acquisition time. One significant problem that tomosynthesis of the breast must overcome, however, is the reduction of x‐ray scatter inclusion in the projection images. In tomosynthesis, due to the projection geometry and radiation dose considerations, the use of an antiscatter grid presents several challenges. Therefore, the use of postacquisition software‐based scatter reduction algorithms seems well justified, requiring a comprehensive evaluation of x‐ray scatter content in the tomosynthesis projections. This study aims to gain insight into the behavior of x‐ray scatter in tomosynthesis by characterizing the scatter point spread functions (PSFs) and the scatter to primary ratio (SPR) maps found in tomosynthesis of the breast. This characterization was performed using Monte Carlo simulations, based on the Geant4 toolkit, that simulate the conditions present in a digital tomosynthesis system, including the simulation of the compressed breast in both the cranio‐caudal (CC) and the medio‐lateral oblique (MLO) views. The variation of the scatter PSF with varying tomosynthesis projection angle, as well as the effects of varying breast glandular fraction and x‐ray spectrum, was analyzed. The behavior of the SPR for different projection angle, breast size, thickness, glandular fraction, and x‐ray spectrum was also analyzed, and computer fit equations for the magnitude of the SPR at the center of mass for both the CC and the MLO views were found. Within mammographic energies, the x‐ray spectrum was found to have no appreciable effect on the scatter PSF and on the SPR. Glandular fraction and compressed breast size were found to have a small effect, while compressed breast thickness and projection angle, as expected, introduced large variations in both the scatter PSF and SPR. The presence of the breast support plate and the detector cover plate in the simulations introduced important effects on the SPR, which are also relevant to the scatter content in planar mammography.
An optical flow based method for improved reconstruction of 4D CT data sets acquired during free breathing
Authors: Ehrhardt Jan , Werner René , Säring Dennis , Frenzel Thorsten , Lu Wei , Low Daniel , Handels Heinz
Published: February 2007

Respiratory motion degrades anatomic position reproducibility and leads to issues affecting image acquisition, treatment planning, and radiation delivery. Four‐dimensional (4D) computer tomography (CT) image acquisition can be used to measure the impact of organ motion and to explicitly account for respiratory motion during treatment planning and radiation delivery. Modern CT scanners can only scan a limited region of the body simultaneously and patients have to be scanned in segments consisting of multiple slices. A respiratory signal (spirometer signal or surface tracking) is used to reconstruct a 4D data set by sorting the CT scans according to the couch position and signal coherence with predefined respiratory phases. But artifacts can occur if there are no acquired data segments for exactly the same respiratory state for all couch positions. These artifacts are caused by device‐dependent limitations of gantry rotation, image reconstruction times and by the variability of the patient's respiratory pattern. In this paper an optical flow based method for improved reconstruction of 4D CT data sets from multislice CT scans is presented. The optical flow between scans at neighboring respiratory states is estimated by a non‐linear registration method. The calculated velocity field is then used to reconstruct a 4D CT data set by interpolating data at exactly the predefined respiratory phase. Our reconstruction method is compared with the usually used reconstruction based on amplitude sorting. The procedures described were applied to reconstruct 4D CT data sets for four cancer patients and a qualitative and quantitative evaluation of the optical flow based reconstruction method was performed. Evaluation results show a relevant reduction of reconstruction artifacts by our technique. The reconstructed 4D data sets were used to quantify organ displacements and to visualize the abdominothoracic organ motion.
Spread‐out Bragg peak and monitor units calculation with the Monte Carlo Code MCNPX
Authors: Hérault J. , Iborra N. , Serrano B. , Chauvel P.
Published: February 2007

The aim of this work was to study the dosimetric potential of the Monte Carlo code MCNPX applied to the protontherapy field. For series of clinical configurations a comparison between simulated and experimental data was carried out, using the proton beam line of the MEDICYC isochronous cyclotron installed in the Centre Antoine Lacassagne in Nice. The dosimetric quantities tested were depth‐dose distributions, output factors, and monitor units. For each parameter, the simulation reproduced accurately the experiment, which attests the quality of the choices made both in the geometrical description and in the physics parameters for beam definition. These encouraging results enable us today to consider a simplification of quality control measurements in the future. Monitor Units calculation is planned to be carried out with preestablished Monte Carlo simulation data. The measurement, which was until now our main patient dose calibration system, will be progressively replaced by computation based on the MCNPX code. This determination of Monitor Units will be controlled by an independent semi‐empirical calculation.
Fully automated segmentation of oncological PET volumes using a combined multiscale and statistical model
Authors: Montgomery David W. G. , Amira Abbes , Zaidi Habib
Published: February 2007

The widespread application of positron emission tomography (PET) in clinical oncology has driven this imaging technology into a number of new research and clinical arenas. Increasing numbers of patient scans have led to an urgent need for efficient data handling and the development of new image analysis techniques to aid clinicians in the diagnosis of disease and planning of treatment. Automatic quantitative assessment of metabolic PET data is attractive and will certainly revolutionize the practice of functional imaging since it can lower variability across institutions and may enhance the consistency of image interpretation independent of reader experience. In this paper, a novel automated system for the segmentation of oncological PET data aiming at providing an accurate quantitative analysis tool is proposed. The initial step involves expectation maximization (EM)‐based mixture modeling using a‐means clustering procedure, which varies voxel order for initialization. A multiscale Markov model is then used to refine this segmentation by modeling spatial correlations between neighboring image voxels. An experimental study using an anthropomorphic thorax phantom was conducted for quantitative evaluation of the performance of the proposed segmentation algorithm. The comparison of actual tumor volumes to the volumes calculated using different segmentation methodologies including standard‐means, spatial domain Markov Random Field Model (MRFM), and the new multiscale MRFM proposed in this paper showed that the latter dramatically reduces the relative error to less than 8% for small lesions (radii) and less than 3.5% for larger lesions (radii). The analysis of the resulting segmentations of clinical oncologic PET data seems to confirm that this methodology shows promise and can successfully segment patient lesions. For problematic images, this technique enables the identification of tumors situated very close to nearby high normal physiologic uptake. The use of this technique to estimate tumor volumes for assessment of response to therapy and to delineate treatment volumes for the purpose of combined PET/CT‐based radiation therapy treatment planning is also discussed.
Reliability analysis framework for computer‐assisted medical decision systems
Authors: Habas Piotr A. , Zurada Jacek M. , Elmaghraby Adel S. , Tourassi Georgia D.
Published: February 2007

We present a technique that enhances computer‐assisted decision (CAD) systems with the ability to assess the reliability of each individual decision they make. Reliability assessment is achieved by measuring the accuracy of a CAD system with known cases similar to the one in question. The proposed technique analyzes the feature space neighborhood of the query case to dynamically select an input‐dependent set of known cases relevant to the query. This set is used to assess the local (query‐specific) accuracy of the CAD system. The estimated local accuracy is utilized as a reliability measure of the CAD response to the query case. The underlying hypothesis of the study is that CAD decisions with higher reliability are more accurate. The above hypothesis was tested using a mammographic database of 1337 regions of interest (ROIs) with biopsy‐proven ground truth (681 with masses, 656 with normal parenchyma). Three types of decision models,a back‐propagation neural network (BPNN),a generalized regression neural network (GRNN), anda support vector machine (SVM), were developed to detect masses based on eight morphological features automatically extracted from each ROI. The performance of all decision models was evaluated using the Receiver Operating Characteristic (ROC) analysis. The study showed that the proposed reliability measure is a strong predictor of the CAD system's case‐specific accuracy. Specifically, the ROC area index for CAD predictions with high reliability was significantly better than for those with low reliability values. This result was consistent across all decision models investigated in the study. The proposed case‐specific reliability analysis technique could be used to alert the CAD user when an opinion that is unlikely to be reliable is offered. The technique can be easily deployed in the clinical environment because it is applicable with a wide range of classifiers regardless of their structure and it requires neither additional training nor building multiple decision models to assess the case‐specific CAD accuracy.
RF/Microwave Interaction with Biological Tissues
Authors: Djajaputra David
Published: February 2007

RF/Microwave Interaction with Biological Tissues Vander Vorst André Rosen Arye Kotsuka Youji. 330 pp., Wiley, Hoboken, NJ, 2006. $95.00. ISBN 0‐471‐73277‐X.
Species-Specific Differences in the Susceptibilities of Biofilms Formed by
Candida
Bloodstream Isolates to Echinocandin Antifungals
Authors: Choi Hyun Woo , Shin Jong Hee , Jung Sook In , Park Kyung Hwa , Cho Duck , Kee Seung Jung , Shin Myung Geun , Suh Soon Pal , Ryang Dong Wook
Published: February 2007

The echinocandin susceptibilities of bloodstream
Candida
isolates growing in a biofilm was investigated. Within the therapeutic range of concentrations of each drug, caspofungin and micafungin were active against biofilms formed by
Candida albicans
or
C. glabrata
but not those formed by
C. tropicalis
or
C. parapsilosis
.
Common Origin and Fixation of
Plasmodium falciparum dhfr
and
dhps
Mutations Associated with Sulfadoxine-Pyrimethamine Resistance in a Low-Transmission Area in South America
Authors: McCollum Andrea M. , Mueller Kristen , Villegas Leopoldo , Udhayakumar Venkatachalam , Escalante Ananias A.
Published: February 2007

Recent studies indicated that sensitive parasites could increase in frequency in a population when drugs are removed, suggesting that the life span of affordable antimalarial drugs could be expanded. We studied 97 samples from Bolivar State, Venezuela, an area where sulfadoxine-pyrimethamine (SP) has not been used for 8 years due to its ineffectiveness. We characterized point mutations in two genes that have been implicated in resistance to SP, dihydrofolate reductase (
dhfr
) and dihydropteroate synthase (
dhps
). We also assayed neutral microsatellite markers around the
dhfr
(chromosome 4) and
dhps
(chromosome 8) genes and on chromosomes 2 and 3 to track the origin and spread of resistant alleles. We found that drug-resistant SP mutants are fixed in the population. Two genotypes were present in the samples,
dhfr
(
50R
/
51I
/
108N
)
dhps
(
437G
/
540E
/
581G
) (90.7%) and
dhfr
(
51I
/
108N
)
dhps
(
437G
/
581G
) (9.3%). We show a single microsatellite haplotype for all of the
dhfr
and
dhps
alleles, and the alleles at the microsatellite loci are different from those present in Africa. Thus, in these samples from Venezuela, there is a single origin for both
dhfr
and
dhps
SP-resistant alleles, and these alleles originated independently of those characterized from Africa. Furthermore, this is the first report of a “hitchhiking effect” on the genetic variation around
dhps
due to selection by SP using an extensive set of microsatellite markers. Our results indicate that, in areas where there is limited gene flow, the fixation of drug-resistant parasites in the population is stable, even after drug selection is relaxed.
Dissemination of
sul3
-Containing Elements Linked to Class 1 Integrons with an Unusual 3′ Conserved Sequence Region among
Salmonella
Isolates
Authors: Antunes Patrícia , Machado Jorge , Peixe Luísa
Published: February 2007

A
sul3
domain (IS
440
-
sul3
-
orf1
-IS
26
) was found linked to an unusual 3′ conserved sequence region (
qacH
) of class 1 integrons and detected among nontyphoid
Salmonella
isolates (
n
= 47) from different sources. Three types of integrons differing in the gene cassette array (
dfrA12
-
orfF
-
aadA2
-
cmlA1
-
aadA1
,
dfrA12
-
orfF
-
aadA2
/
1
, and
estX
-
psp
-
aadA2
-
cmlA1
-
aadA1
) were found associated with this
sul3
domain. They were associated with particular clones and specific high-molecular-weight plasmids.
Molecular Epidemiology of Macrolide and Tetracycline Resistances in Commensal
Gemella
sp. Isolates
Authors: Zolezzi Paula Cerdá , Cepero Pilar Goñi , Ruiz Joaquim , Laplana Leticia Millán , Calvo Carmen Rubio , Gómez-Lus Rafael
Published: February 2007

The epidemiologic relatedness of 29 erythromycin-resistant
Gemella
sp. strains from normal flora, characterized previously, were evaluated by pulsed-field gel electrophoresis (PFGE). Three isolates carried the
tet
(O) gene and the
tet
(M) gene. The
msr
(A) gene was found in two
Gemella morbillorum
strains in combination with the
erm
(B) or
mef
(E) gene. The sequences of the
mef
(A/E
)
,
erm
(B), and
msr
(A) genes showed a high similarity to the corresponding sequences of other gram-positive cocci. All the strains harboring the
mef
(A/E) gene and the
msr
(D) gene possessed open reading frame 3 (ORF3)/ORF6. The 16
G. morbillorum
isolates represented 15 distinct DNA profiles. Four clusters were identified (≥80% genetic relatedness). The 12
Gemella haemolysans
strains belonged to different PFGE types. The clonal diversity found suggests that horizontal transfer may be the main route through which erythromycin resistance is acquired.
In Vitro and In Vivo Activities of Synthetic Trioxolanes against Major Human Schistosome Species
Authors: Xiao Shu-Hua , Keiser Jennifer , Chollet Jacques , Utzinger Jürg , Dong Yuxiang , Endriss Yvette , Vennerstrom Jonathan L. , Tanner Marcel
Published: February 2007

Schistosomiasis is a parasitic disease that remains of considerable public health significance in tropical and subtropical environments. Since the mainstay of schistosomiasis control is chemotherapy with a single drug, praziquantel, drug resistance is a concern. Here, we present new data on the antischistosomal properties of representative synthetic 1,2,4-trioxolanes (OZs). Exposure of adult
Schistosoma mansoni
for 24 h to a medium containing 20 μg/ml OZ209 reduced worm motor activity, induced tegumental alterations, and killed worms within 72 h. While exposure of
S. mansoni
to OZ78 had no apparent effect, addition of hemin reduced worm motor activity and caused tegumental damage. Administration of single 200-mg/kg of body weight oral doses of OZ78, OZ209, and OZ288 to mice harboring a juvenile
S. mansoni
infection resulted in worm burden reductions of 82.0 to 95.4%. In the adult infection model in mice, single 400-mg/kg doses of these compounds resulted in a maximum total worm burden reduction of 52.2%. High worm burden reductions (71.7 to 86.5%) were observed after administration of single 200-mg/kg doses of OZ78 and OZ288 to hamsters infected with either juvenile or adult
S. mansoni
. A single 200-mg/kg dose of OZ78 to hamsters infected with adult
Schistosoma japonicum
resulted in total and female worm burden reductions of 94.2 to 100%. Our results, along with the low toxicity, metabolic stability, and good pharmacokinetic properties of the OZs, indicate the potential for the development of novel broad-spectrum antischistosomal OZ drug candidates.