bluuebunny/crossref_metadata_2025 huggingface dataset:
Frenular Grafting: An Alternative to Circumcision in Men with a Combination of Tight Frenulum and Phimosis
Authors: Kayes Oliver , Li Chi-Ying , Spillings Amanda , Ralph David
Published: May 2007

Introduction

Men suffering from frenular scarring and stricturing with associated phimosis are traditionally treated with circumcision. In men wishing to retain their foreskin, the treatment options are limited by this dual pathology. Frenuloplasty alone is contraindicated in this clinical setting.

Aim

To demonstrate the utility of frenular grafting in patients with a tight frenulum and concomitant phimosis who wish to retain their foreskin.

Methods

Six men were included in the study. Presenting symptoms included bleeding (N = 2) and pain/phimosis (N = 6). Median age is 27 years (25–34 years). All men were healthy and sexually active. We describe a refined technique involving the excision of scarred and redundant frenular tissue and the insertion of a skin graft to the area.

Main Outcome Measures

All patients were assessed for graft viability, functional/symptom improvement, time to penetrative intercourse, and overall satisfaction.

Results

All men received an interposition skin graft with 100% viability, with no revision surgery required. Postoperatively, all men were sexually active and able to retract their foreskin.

Conclusions

Cosmetic outcomes are encouraging and painless sexual intercourse is attainable in this difficult group of patients.
Differential Effects of Hunting on Pre‐Dispersal Seed Predation and Primary and Secondary Seed Removal of Two Neotropical Tree Species
Authors: Beckman Noelle G. , Muller‐Landau Helene C.
Published: May 2007

Many of the mammals undergoing drastic declines in tropical forests worldwide are important seed dispersers and seed predators, and thus changes in mammal communities due to hunting will affect plant recruitment. It has been hypothesized that larger‐seeded species will suffer greater reductions in seed removal and thus greater increases in predispersal seed predation than smaller‐seeded species. We compared primary and secondary seed removal and predispersal seed predation of two tree species between hunted and nonhunted sites in Central Panama. Seeds of Oenocarpus mapora (Arecaceae) are 16‐times greater in size than those of Cordia bicolor (Boraginaceae). We quantified primary seed removal and predispersal seed predation using seed traps, and we assessed secondary seed removal using seed removal plots. Primary removal of C. bicolor was 43 percent lower in the hunted sites, while primary removal of O. mapora was not significantly different. Secondary removal of unprotected O. mapora seeds on the ground was 59 percent lower in hunted sites, while secondary removal of C. bicolor was not significantly different. Predispersal seed predation of O. mapora by mammals was significantly lower in hunted sites, while predispersal seed predation by insects was not significantly different in either species. In combination with other studies, our results suggest that seed size is not a reliable predictor of the impacts of hunting. Mammal defaunation differentially affects stages and modes of seed dispersal and seed predation of different plant species, suggesting that these influences are complex and related to multiple plant traits.
Size‐Related Differential Seed Predation in a Heavily Defaunated Neotropical Rain Forest
Authors: Dirzo Rodolfo , Mendoza Eduardo , Ortíz Patricia
Published: May 2007

Hunting and habitat loss represent an increasingly common anthropogenic impact. Available evidence suggests that defaunation is typically differential: medium/large mammals are most affected while small rodents are less affected, or even favored. In heavily impacted areas, such as Los Tuxtlas, the residual mammalian fauna is dominated by small rodents. We tested the expectation that if small rodents will preferentially attack small‐seeded species, large‐seeded species may escape predation in the absence of medium/large seed predators and that this may affect germination and, possibly, recruitment. Experiments with caged rodents (Heteromys desmarestianus) under laboratory conditions showed a preference for smaller seeds. A field experiment involving seeds of contrasting size showed that small, unprotected seeds experienced a predation risk 30‐times larger than protected seeds, while the effect of protection was not significant for large seeds. These patterns of predation led to significant differences in germination: protected small‐seeded species had a fourfold greater germination than unprotected small‐seeded species, while germination was not significantly different between exposed and protected large seeds. The observed contrasts in germination suggest that under heavy defaunation, small‐seeded species are likely to be penalized by the overabundance of small rodents, while large‐seeded species escape predation. Our results are consistent with the observation of dense seedling carpets dominated by large‐seeded species in the understory of Los Tuxtlas. We speculate that the patterns we uncovered may explain, at least partly, the impoverished diversity of the understory vegetation that characterizes heavily defaunated understories and that this has the potential to affect forest regeneration.
Hunting of Mammals Reduces Seed Removal and Dispersal of the Afrotropical Tree Antrocaryon klaineanum (Anacardiaceae)
Authors: Wang Benjamin C. , Sork Victoria L. , Leong Misha T. , Smith Thomas B.
Published: May 2007

Throughout the tropics, mammalian seed dispersers are being driven to local extinction by intense hunting pressure, generating concern not only about the loss of these species, but also about the consequences for the plants they disperse. We compared two rain forest sites in Cameroon—one with heavy hunting pressure and one protected from hunting—to appraise the loss of mammalian seed dispersers and to assess the impact of this loss on seed removal and seed dispersal of Antrocaryon klaineanum (Anacardiaceae), a mammal‐dispersed tree. Surveys of arboreal frugivores indicate that three of the five monkey species, as well as chimpanzee and gorilla, have been extirpated from the hunted forest. Diaspore counts underneath A. klaineanum adults (six trees per site) indicate that seed removal is severely reduced in the hunted forest. Finally, genetic maternity exclusion analysis (using 3–7 nuclear microsatellite loci) of maternally inherited endocarp tissue from diaspores collected under the canopies of 12 fruiting “mother” trees (six trees per site) revealed that seed dispersal in the hunted forest is also greatly reduced. In the hunted forest with reduced mammal dispersal agents, only 1 of the 53 assayed endocarps (2%) did not match the mother and was determined to be from a dispersed diaspore. By contrast, in the protected forest, 20 of the 48 assayed endocarps (42%) were from dispersed diaspores. This study provides strong evidence that loss of dispersal agents can lead to reduced seed removal and loss of seed dispersal, disrupting the seed dispersal cycle.
The sizes of disc galaxies in intermediate-redshift clusters
Authors: Bamford S. P. , Milvang-Jensen B. , Aragón-Salamanca A.
Published: May 2007

We examine how the location of star formation within disc galaxies depends on environment at intermediate redshift. This is achieved by comparing emission-line (rem) and rest-frame B-band (rB) scalelengths for matched samples of 50 field and 19 cluster, star-forming, disc galaxies, with 0.25 ⩽z⩽ 1.0 and MB⩽−19.5 mag. We find that at a given rB the majority of our cluster galaxies have rem smaller than those in the field, by 25 per cent on average. These results are compared with studies of local galaxies, which find a very similar behaviour. From the relations of rem and rB versus B-band absolute magnitude (MB) we infer that the difference between the intermediate-z cluster and field samples is mostly attributable to variation in rem at a given MB, while the rB versus MB relation is similar for the two samples.
On spherically symmetrical accretion in fractal media
Authors: Roy Nirupam
Published: May 2007

We use fractional integrals to generalize the description of hydrodynamic accretion in fractal media. The fractional continuous medium model allows the generalization of the equations of balance of mass density and momentum density. These make it possible to consider the general case of spherical hydrodynamic accretion on to a gravitating mass embedded in a fractal medium. The general nature of the solution is similar to the ‘Bondi solution’, but the accretion rate may vary substantially and the dependence on central mass may change significantly depending on dimensionality of the fractal medium. The theory shows consistency with the observational data and numerical simulation results for the particular case of accretion on to pre-main-sequence stars.
EFFECT OF ELECTRICAL STIMULATION, SUSPENSION METHOD AND AGING ON BEEF TENDERNESS OF THE BONSMARA BREED
Authors: DERBYSHIRE W. , LUES J.F.R. , JOUBERT G. , SHALE K. , JACOBY A. , HUGO A.
Published: May 2007

In this study, the effect of electrical stimulation (ES), suspension method (SM) and aging on the tenderness of the Longissimus lumborum (LL) of 32 Bonsmara steer carcasses was investigated. After slaughtering, half of the carcasses (16) used in the study were electrically stimulated, and after dressing all 32 carcasses were split into halves and 16 electrically stimulated and 16 nonelectrically stimulated halves were hip suspended while the remaining halves were Achilles suspended. After a 24‐h chill, the LL was removed and divided into half. Half of the LL samples were designated to the 24‐h aging treatment and frozen, while the other half was vacuum packed and aged for 7 days. Small samples were removed from the 24‐h and 7‐day aged samples for determination of sarcomere lengths. Sarcomere lengths were significantly increased by hip suspension, but were not affected by ES, as well as by aging in combination with ES or suspension. Tenderness was measured by means of shear force, and cooking data were recorded. When applied individually, all the treatments significantly reduced the shear force of the meat; however, in combinations, the treatments had a cumulative effect, especially when carcasses were Achilles suspended. The SM, aging and ES had no effect on the cooking data.
City Marketing: The Past, the Present and Some Unresolved Issues
Authors: Kavaratzis Mihalis
Published: May 2007

For several decades now, cities all over the world have been applying marketing techniques and increasingly adopting a marketing philosophy to meet their operational and strategic goals. City marketing has grown into an established field of research and an academic subdiscipline. This article begins with a description of the three main historical episodes of city marketing development and then assesses its current state, suggesting that cities have moved into a fourth episode, which centres on the application of city branding. Despite the accumulated experience, however, many issues surrounding the application of city marketing remain in need of further theoretical development and practical clarification. The last part of this article therefore seeks to further the discussion about the effects of city marketing, seeking to elicit the latent potential that city marketing might still hold for the future prospects of cities.
Climate Science and Decision Making
Authors: Dow Kirstin , Carbone Gregory
Published: May 2007

This article reviews progress in understanding climate variability and change and how such understanding might better contribute to decision processes and the design of decision support tools. We emphasize the value of collaborative engagement between climate information users and scientists to continue innovation in this area. Our assessment presents opportunities for geographic perspectives and insights that can increase understanding of the physical processes causing interannual variability and improve climate model output for climate impact assessment. As decision‐makers’ interests expand to address adaptation, nature‐society research can also contribute significantly to understanding the diversity of climate information users, their evolving needs, and to the development of strategies for communicating risk and uncertainty.
Climate Change and Human Health
Authors: Comrie Andrew
Published: May 2007

What kinds of climate‐mediated diseases exist, and how are projected climate changes expected to alter their spread and timing? Disease is produced in a complex way, through coupled interactions between natural and human systems. Climate is a major factor controlling ecosystem variability and therefore the potential for outbreaks of certain diseases. Yet, the concept of vulnerability shows how overall disease risk depends not only on the environmental exposure, but also on the sensitivity and adaptive capacity of the group and place experiencing it. These interactions between environment and society are highlighted through a set of climate‐related diseases, ranging from direct to complex relationships, including extreme heat, air pollution, aeroallergens, fungi, water‐ and food‐borne diseases, influenza, rodent‐borne diseases, and insect‐borne diseases.
Sensory Profiles of Bread Made from Paired Samples of Organic and Conventionally Grown Wheat Grain
Authors: Annett L.E. , Spaner D. , Wismer W.V.
Published: May 2007

ABSTRACT: The Canadian hard red spring wheat cultivar “Park” was grown in 2005 in Edmonton, AB, Canada on both conventionally and organically managed land, situated less than 1 km apart. Grains from the paired wheat samples were compared for cereal‐grain‐quality attributes. For sensory analysis, organically and conventionally produced wheat grains were milled into flour and baked into 60% whole wheat bread. Color, texture, taste, and aroma attributes of bread were compared using the sensory technique of descriptive analysis. Organic grain contained more wholemeal protein than conventional grain (P≤ 0.05), but both were greater than 14% protein, indicating excellent grain quality for yeast‐leavened bread. Mixograph analysis revealed that conventional flour produced stronger bread dough than organic flour (P≤ 0.05). Visual observation confirmed these findings as conventional flour produced larger bread loaf volume. Fourteen sensory attributes were generated by the descriptive analysis panel. No differences were observed for flavor, aroma, or color attributes (P> 0.05), but the panel perceived the organic bread to be more “dense” in texture (P≤ 0.05) with smaller air cells in the appearance of the crumb (P≤ 0.05) than conventional bread.
Electron Beam Irradiation Improves Shelf Lives of Korean Ginseng (Panax ginseng C.A. Meyer) and Red Ginseng
Authors: Jin Y. , Shin H. , Song K.B.
Published: May 2007

ABSTRACT:  Effect of electron beam irradiation on microbial growth and qualities of vacuum‐packaged Korean ginseng and red ginseng during storage was investigated. Korean ginseng and red ginseng were treated at irradiation doses of 0, 2, 8, and 16 kGy. After treatment, samples were individually vacuum‐packaged and stored at 20 °C. Microbial growth results of the irradiated samples presented that populations of total bacteria, yeast and mold, and total coliforms were decreased by 2 to 3 log CFU/g. The pH values of the samples were not significantly different among treatments. Thiobarbituric acid‐reactive substance values of the samples increased during storage. Electron beam treatment caused negligible changes in Hunter's color L, a, and b values among the samples. Sensory evaluations like color and odor of the samples exhibited that there were no significant changes among the samples. During storage, content of saponin, a leading compound in ginseng, was not affected by irradiation. These results suggest that electron beam treatment should be useful in extending shelf lives of Korean ginseng and red ginseng.
A LONGITUDINAL COMPARISON OF THE ORTHODONTIC TREATMENT PRIORITY INDEX AND THE SUBJECTIVE APPRAISAL OF THE ORTHODONTIST*
Authors: Popovich Frank , Thompson G. W.
Published: April 2007

Drs. Popovich and Thompson, with usual Canadian thoroughness, have worked with a method of assessing priority of treatment for malocclusion which goes far to eliminate the subjective decisions of orthodontists.
THE ROLE OF RADIOGRAPHS IN CLINICAL STUDIES OF CARIES‐INHIBITORY AGENTS
Authors: Richardson Alan S. , Hole Len , Williams Jime F.
Published: April 2007

Dr. Richardson and his group have performed considerable service in their analytical study of the benefit which might arise from the addition of radiographs to mass examinations.
ABNORMALITIES OF BONE AND OROFACIAL CHANGES FROM ANTICONVULSANT DRUGS
Authors: Israel Harry
Published: April 2007

Dr. Israel, from his experience at the Fels Research Institute, presents an earnest plea for a critical consideration of the orofacial changes from medication with anticonvulsants.
Utility of the Dental Aesthetic Index in Industrialized and Developing Countries
Authors: Cons Naham C. , Jenny Joanna , Kohout Frank J. , DDS Yupin Songpaisan , Jotikastira Dirawathana
Published: April 2007

To be truly useful, an index must be applicable universally without modification. The data presented in this article support the use of the standard DAI without modification to assess need for orthodontic treatment in both developing and industrialized countries. When students from Thailand, Australia, the German Democratic Republic, and Native Americans residing on Indian reservations rated the same 25 occlusal stimuli (photographs of dental configurations) for dental aesthetics, their ratings of these stimuli when arranged in rank order were highly correlated with those of US students. These 25 occlusal stimuli were a subset of the original 200 occlusal stimuli used in deriving the standard DAI regression equation.

This article presents data indicating that when a Native American DAI was derived based on Native American ratings of the same 200 occlusal stimuli used in deriving the standard DAI, the Native American DAI and the standard DAI had the same ten components (orthodontic measurements) and strikingly similar regression coefficients (weights). Further analysis indicated that the two equations were sufficiently similar to justify using the standard DAI to obtain DAI scores on Native Americans and to estimate the relative social acceptability of their dental aesthetics.

If ratings for dental aesthetics for the full set of 200 stimuli were available for each of the countries where only 25 were rated, we expect that, as in the case of Native Americans, a country‐specific DAI, if computed, would be sufficiently similar to the standard DAI that no modification would be needed to allow use of the standard DAI in that country. We conclude that the standard DAI could have utility in both developing and industrialized countries to assess need for orthodontic treatment.
Issues in Financing Dental Care for the Elderly
Authors: Jones Judith A. , Adelson Richard , Nlessen Linda C. , Gilbert Gregg H.
Published: April 2007

The elderly make up an increasingly larger segment of the patient population in dental practices. This article reviews recent epidemiologic, demographic, and health services research, and concludes that significant segments of the elderly are at high risk for oral disease and/or limited access to dental treatment, and consequently warrant classification as high‐risk groups for policy considerations. It then proposes policy options to the dental community and public policy decision makers. Oral care can be viewed as having three components. Two basic components are the primary care component–which includes diagnostic, preventive, restorative, and periodontal care–and the acute care component–i.e., the treatment of oral pain, trauma, and infection. The third, rehabilitative component, has to do with the restoration of oral function, including prosthodontics and cosmetic dentistry. Viewing dental care in this perspective may help link funding for dental primary care services with that for other primary health services, and link restoration of function and improvement of quality of life with similar health services, like hearing, vision, and social services. In addition, approaching dental care policy makers on several levels–i.e., federal, state, and local–will contribute to our ability as a profession, in the decades ahead, to meet the oral health needs of more elders: including the frail, those at high risk for oral disease, and those with limited access to care.
Statistical Methodologies Useful for the Analysis of Data from Risk‐assessment Studies
Authors: Koch Gary G. , Beck James D.
Published: April 2007

in dentistry, the vast majority of studies attempting to predict who is at high risk for getting a disease or condition, or attempting to identify risk factors for a specific disease or condition, have focused either on only one risk factor at a time, or have measured multiple potential risk factors, but analyzed their effects in isolation. Since researchers tend to agree that most dental conditions have a multiple etiology, it is necessary to develop models that consider simultaneously the effect of a number of potential risk factors on the disease or condition of interest if we are to have any understanding of the relative impact of potential risk factors. Many existing statistical techniques will aid dental researchers in identifying risk factors. However, the selection of an appropriate analytic technique depends on a number of conditions. The strategy for this paper is to discuss a wide range of possible statistical techniques that may be applied to the problem of deriving a model for identification of multiple risk factors for dental diseases and conditions. We have approached this task by presenting a number of dental research problems needing an appropriate analytic technique. Next, basic issues that must be considered in choosing an appropriate analytic strategy are discussed. These issues include features of the study design, the data structure of the variables being measured, and the types of assumptions that are applicable to provide valid inferences about the target population of interest. A matrix of possible analytic techniques is presented for various combinations of study‐design and data‐structure features. After a discussion of each of the techniques, the appropriate statistical techniques for each of the dental examples are described. The issues and examples presented in this paper should be of use to dental researchers who wish to investigate multiple risk factors for a disease or condition of interest.
The Need for Toothpastes with Lower than Conventional Fluoride Concentrations for Preschool‐aged Children
Authors: Horowitz Herschel S.
Published: April 2007

Since 1945, when community water fluoridation was first implemented in the United States, not only has the procedure grown to cover more than half of the US population, but the development and use of other fluoride methods have expanded greatly. A concomitant, dramatic decrease has occurred in the caries prevalence of US school‐aged children. Recent studies indicate, how‐ever, that the prevalence and, to a lesser extent, the intensity of dental fluorosis have increased in schoolchildren in both fluoridated and fluoride‐deficient areas. Several studies show that young children inadvertently ingest sizable proportions of toothpaste during toothbrushing. Although ingestion of fluoride toothpastes by preschool‐aged children may not be the major contributor to the increase in fluorosis, the findings of at least four studies suggest that the use of fluoride toothpastes by young children is a risk factor. The direct dose‐response relation between effectiveness and fluoride concentration of toothpastes is far from clear‐cut and, at best, is weak. Thus, considering today's reduced risk of caries, it is timely to market fluoride toothpastes in the US with 400–500 ppm fluoride for preschool‐aged children, who are still at risk for developing fluorosis, as has been done in several other countries. Dental public health authorities must work with toothpaste manufacturers, professional organizations, and regulatory agencies to facilitate the approval and marketing of such pediatric fluoride tooth‐pastes.
Feather stable‐isotope profiles reveal stopover habitat selection and site fidelity in nine migratory species moving through sub‐Saharan Africa
Authors: Yohannes Elizabeth , Hobson Keith A. , Pearson David J.
Published: May 2007

Stable nitrogen (δ15N), carbon (δ13C) and hydrogen (δD) isotope profiles in feathers of nine migratory bird species trapped in Kenya were examined to test the extent to which they were segregated, geographically or by habitat, during an earlier autumn migration stopover in northeast Africa. We examined whether isotopic differences between species varied between years, and whether the isotope profiles of individual species appeared to be consistent. The relationship between mean feather δ13C, δ15N and δD assorted the migrants into several clustered groups. Similar feather isotope values among successive years revealed that each species tended to return to the same or similar stopover areas and selected habitat and diet that generated similar isotopic signatures. Possible explanations are discussed for the existence of these isotopic groups.
Effectiveness of a commonly‐used technique for experimentally reducing plumage UV reflectance
Authors: Korsten Peter , Limbourg Tobias , Lessells Catherine M. , Komdeur Jan
Published: May 2007

Ultraviolet (UV) plumage is thought to be sexually selected through intra‐sexual competition, female choice and differential allocation. Experimental manipulations of plumage UV reflectance are essential to demonstrate that mate choice or intra‐sexual competition are causally related to UV coloration. The most widely‐used technique for manipulating UV reflectance in wild birds is the application of a mixture of UV‐absorbing chemicals and preen gland fat. However, although this UV reduction technique is commonly used, little is known about the persistence of the treatment and the temporal variation in UV reflectance that it causes. We manipulated the UV crown plumage of wild and captive blue tits Parus caeruleus, and took repeated photospectrometric measurements of both UV‐reduced and control‐treated individuals. Our results show that the UV reduction lasts for at least five days and that the treatment has no negative effects on the survival of wild birds.
Tomographic digital subtraction angiography for lung perfusion estimation in rodents
Authors: Badea Cristian T. , Hedlund Laurence W. , De Lin Ming , Boslego Mackel Julie S. , Samei Ehsan , Johnson G. Allan
Published: May 2007

In vivo measurements of perfusion present a challenge to existing small animal imaging techniques such as magnetic resonance microscopy, micro computed tomography, micro positron emission tomography, and microSPECT, due to combined requirements for high spatial and temporal resolution. We demonstrate the use of tomographic digital subtraction angiography (TDSA) for estimation of perfusion in small animals. TDSA augments conventional digital subtraction angiography (DSA) by providing three‐dimensional spatial information using tomosynthesis algorithms. TDSA is based on the novel paradigm that the same time density curves can be reproduced in a number of consecutive injections of volumes of contrast at a series of different angles of rotation. The capabilities of TDSA are established in studies on lung perfusion in rats. Using an imaging system developed in‐house, we acquired data for four‐dimensional (4D) imaging with temporal resolution of , in‐plane spatial resolution of , and slice thickness on the order of millimeters. Based on a structured experimental approach, we optimized TDSA imaging providing a good trade‐off between slice thickness, the number of injections, contrast to noise, and immunity to artifacts. Both DSA and TDSA images were used to create parametric maps of perfusion. TDSA imaging has potential application in a number of areas where functional perfusion measurements in 4D can provide valuable insight into animal models of disease and response to therapeutics.
Film dosimetry calibration method for pulsed‐dose‐rate brachytherapy with an source
Authors: Schwob Nathan , Orion Itzhak
Published: May 2007

sources have been widely used in clinical brachytherapy. An important challenge is to perform dosimetric measurements close to the source despite the steep dose gradient. The common, inexpensive silver halide film is a classic two‐dimensional integrator dosimeter and would be an attractive solution for these dose measurements. The main disadvantage of film dosimetry is the film response to the low‐energy photon. Since the photon energy spectrum is known to vary with depth, the sensitometric curves are expected to be dependent on depth. The purpose of this study is to suggest a correction method for silver halide film dosimetry that overcomes the response changes at different depths. Sensitometric curves have been obtained at different depths with verification film near a 1 Cipulsed‐dose‐rate source. The depth dependence of the film response was observed and a correction function was established. The suitability of the method was tested through measurement of the radial dose profile and radial dose function. The results were compared to Monte Carlo‐simulated values according to the TG43 formalism. Monte Carlo simulations were performed separately for the beta and gamma source emissions, using the EGS4 code system, including the low‐energy photon and electron transport optimization procedures. The beta source emission simulation showed that the beta dose contribution could be neglected and therefore the film‐depth dependence could not be attributed to this part of the source radioactivity. The gamma source emission simulations included photon‐spectra collection at several depths. The results showed a depth‐dependent softening of the photon spectrum that can explain the film‐energy dependence.
A fast algorithm for gamma evaluation in 3D
Authors: Wendling Markus , Zijp Lambert J. , McDermott Leah N. , Smit Ewoud J. , Sonke Jan‐Jakob , Mijnheer Ben J. , van Herk Marcel
Published: May 2007

The ‐evaluation method is a tool by which dose distributions can be compared in a quantitative manner combining dose‐difference and distance‐to‐agreement criteria. Since its introduction, the evaluation has been used in many studies and is on the verge of becoming the preferred dose distribution comparison method, particularly for intensity‐modulated radiation therapy (IMRT) verification. One major disadvantage, however, is its long computation time, which especially applies to the comparison of three‐dimensional (3D) dose distributions. We present a fast algorithm for a full 3D evaluation at high resolution. Both the reference and evaluated dose distributions are first resampled on the same grid. For each point of the reference dose distribution, the algorithm searches for the best point of agreement according to the method in the evaluated dose distribution, which can be done at a subvoxel resolution. Speed, computer memory efficiency, and high spatial resolution are achieved by searching around each reference point with increasing distance in a sphere, which has a radius of a chosen maximum search distance and is interpolated “on‐the‐fly” at a chosen sample step size. The smaller the sample step size and the larger the differences between the dose distributions, the longer the evaluation takes. With decreasing sample step size, statistical measures of the 3D distribution converge. Two clinical examples were investigated using 3% of the prescribed dose as dose‐difference and as distance‐to‐agreement criteria. For grid spacing, the change in indices was negligible below a sample step size of . Comparing the full 3D evaluation and slice‐by‐slice 2D evaluations (“2.5D”) for these clinical examples, the indices improved by searching in full 3D space, with the average index decreasing by at least 8%.
Segmentation and leaf sequencing for intensity modulated arc therapy
Authors: Gladwish Adam , Oliver Mike , Craig Jeff , Chen Jeff , Bauman Glenn , Fisher Barbara , Wong Eugene
Published: May 2007

A common method in generating intensity modulated radiation therapy (IMRT) plans consists of a three step process: an optimized fluence intensity map (IM) for each beam is generated via inverse planning, this IM is then segmented into discrete levels, and finally, the segmented map is translated into a set of MLC apertures via a leaf sequencing algorithm. To date, limited work has been done on this approach as it pertains to intensity modulated arc therapy (IMAT), specifically in regards to the latter two steps. There are two determining factors that separate IMAT segmentation and leaf sequencing from their IMRT equivalents: (1) the intrinsic 3D nature of the intensity maps (standard 2D maps plus the angular component), and (2) that the dynamic multileaf collimator (MLC) constraints be met using a minimum number of arcs. In this work, we illustrate a technique to create an IMAT plan that replicates Tomotherapy deliveries by applying IMAT specific segmentation and leaf‐sequencing algorithms to Tomotherapy output sinograms. We propose and compare two alternative segmentation techniques, a clustering method, and a bottom‐up segmentation method (BUS). We also introduce a novel IMAT leaf‐sequencing algorithm that explicitly takes leaf movement constraints into consideration. These algorithms were tested with 51 angular projections of the output leaf‐open sinograms generated on the Hi‐ART II treatment planning system (Tomotherapy Inc.). We present two geometric phantoms and 2 clinical scenarios as sample test cases. In each case 12 IMAT plans were created, ranging from 2 to 7 intensity levels. Half were generated using the BUS segmentation and half with the clustering method. We report on the number of arcs produced as well as differences between Tomotherapy output sinograms and segmented IMAT intensity maps. For each case one plan for each segmentation method is chosen for full Monte Carlo dose calculation (NumeriX LLC) and dose volume histograms (DVH) are calculated. In all cases, the BUS method outperformed the clustering, method. We recommend using the BUS algorithm and discuss potential improvements to the clustering algorithms.
Quantum‐Mechanical Signal Processing and Spectral Analysis
Authors: Xu Andy
Published: May 2007

Quantum‐Mechanical Signal Processing and Spectral Analysis Belkić Dźevad 463 pp., Institute of Physics Publishing, Temple Black, Bristol, UK, 2005. $135.00 (Hardcover). ISBN 0‐7503‐1019‐7.
Roadless Space of the Conterminous United States
Authors: Watts Raymond D. , Compton Roger W. , McCammon John H. , Rich Carl L. , Wright Stewart M. , Owens Tom , Ouren Douglas S.
Published: May 2007

Roads encroaching into undeveloped areas generally degrade ecological and watershed conditions and simultaneously provide access to natural resources, land parcels for development, and recreation. A metric of roadless space is needed for monitoring the balance between these ecological costs and societal benefits. We introduce a metric, roadless volume (RV), which is derived from the calculated distance to the nearest road. RV is useful and integrable over scales ranging from local to national. The 2.1 million cubic kilometers of RV in the conterminous United States are distributed with extreme inhomogeneity among its counties.
Organisms Designated as
Nocardia asteroides
Drug Pattern Type VI Are Members of the Species
Nocardia cyriacigeorgica
Authors: Conville Patricia S. , Witebsky Frank G.
Published: May 2007

Nocardia cyriacigeorgica
has recently been described as an “emerging” pathogen. However, DNA-DNA hybridization results confirm that
Nocardia asteroides
drug pattern type VI, which has long been recognized as a common and significant pathogen in the United States, belongs to the species
N. cyriacigeorgica
.
Fatal Bioprosthetic Aortic Valve Endocarditis Due to
Cardiobacterium valvarum
Authors: Geißdörfer Walter , Tandler René , Schlundt Christian , Weyand Michael , Daniel Werner G. , Schoerner Christoph
Published: May 2007

Cardiobacterium valvarum
was isolated from the blood of a 71-year-old man with fatal aortic valve endocarditis. The API NH system was used for phenotypic characterization of the
C. valvarum
strain. This is the first case of infective endocarditis caused by
C. valvarum
in Germany and the first case worldwide affecting a prosthetic valve and lacking an obvious dental focus.
Isolation and Propagation of the Ap-Variant 1 Strain of
Anaplasma phagocytophilum
in a Tick Cell Line
Authors: Massung Robert F. , Levin Michael L. , Munderloh Ulrike G. , Silverman David J. , Lynch Meghan J. , Gaywee Jariyanart K. , Kurtti Timothy J.
Published: May 2007

The first tissue culture isolates of the unique
Anaplasma phagocytophilum
strain, Ap-Variant 1, were obtained in the
Ixodes scapularis
tick-derived cell line ISE6. Two isolates were from goat blood samples: one from a goat infected with
I. scapularis
ticks from Rhode Island and a second from a goat infected by serial passage of blood from the first infected goat. Eight isolates were made directly from
I. scapularis
ticks collected from white-tailed deer in Minnesota and represent the first isolations of an
Anaplasma
species directly from ticks. Each of the 10 isolates had a 16S rRNA gene sequence identical to that previously described for Ap-Variant 1, but differences within the
ank
gene were found that suggest natural variation. Prevalence of
Anaplasma
in the Minnesota ticks was 63.9%; 23 of 36 ticks tested by PCR were positive. Six of the tick-derived isolates were obtained from a set of 18 PCR-positive ticks, for a 33.3% isolation success rate. The conservation of host tropism among the Rhode Island and Minnesota isolates of Ap-Variant 1 was examined by use of experimental infections of mice and a goat. A Minnesota tick-derived isolate (MN-61-2) was used to inoculate naïve animals, and this isolate was able to infect a goat but unable to infect each of five mice, confirming that the Minnesota isolates have the same host tropism as Ap-Variant 1 from the northeastern United States. Light and electron microscopy of the Ap-Variant 1 isolate MN-61-2 in ISE6 cells showed cytoplasmic inclusions characteristic of
A. phagocytophilum
with pleomorphic bacteria in membrane-bound vacuoles and both electron-dense and electron-lucent forms.
Temporal Analysis of Andes Virus and Sin Nombre Virus Infections of Syrian Hamsters
Authors: Wahl-Jensen Victoria , Chapman Jennifer , Asher Ludmila , Fisher Robert , Zimmerman Michael , Larsen Tom , Hooper Jay W.
Published: May 2007

Andes virus (ANDV) and Sin Nombre virus (SNV) are rodent-borne hantaviruses that cause a highly lethal hemorrhagic fever in humans known as hantavirus pulmonary syndrome (HPS). There are no vaccines or specific drugs to prevent or treat HPS, and the pathogenesis is not understood. Syrian hamsters infected with ANDV, but not SNV, develop a highly lethal disease that closely resembles HPS in humans. Here, we performed a temporal pathogenesis study comparing ANDV and SNV infections in hamsters. SNV was nonpathogenic and viremia was not detected despite the fact that all animals were infected. ANDV was uniformly lethal with a mean time to death of 11 days. The first pathology detected was lymphocyte apoptosis starting on day 4. Animals were viremic and viral antigen was first observed in multiple organs by days 6 and 8, respectively. Levels of infectious virus in the blood increased 4 to 5 logs between days 6 and 8. Pulmonary edema was first detected ultrastructurally on day 6. Ultrastructural analysis of lung tissues revealed the presence of large inclusion bodies and substantial numbers of vacuoles within infected endothelial cells. Paraendothelial gaps were not observed, suggesting that fluid leakage was transcellular and directly attributable to infecting virus. Taken together, these data imply that HPS treatment strategies aimed at preventing virus replication and dissemination will have the greatest probability of success if administered before the viremic phase; however, because vascular leakage is associated with infected endothelial cells, a therapeutic strategy targeting viral replication might be effective even at later times (e.g., after disease onset).
Influenza Virus Hemagglutinin and Neuraminidase, but Not the Matrix Protein, Are Required for Assembly and Budding of Plasmid-Derived Virus-Like Particles
Authors: Chen Benjamin J. , Leser George P. , Morita Eiji , Lamb Robert A.
Published: May 2007

For influenza virus, we developed an efficient, noncytotoxic, plasmid-based virus-like particle (VLP) system to reflect authentic virus particles. This system was characterized biochemically by analysis of VLP protein composition, morphologically by electron microscopy, and functionally with a VLP infectivity assay. The VLP system was used to address the identity of the minimal set of viral proteins required for budding. Combinations of viral proteins were expressed in cells, and the polypeptide composition of the particles released into the culture media was analyzed. Contrary to previous findings in which matrix (M1) protein was considered to be the driving force of budding because M1 was found to be released copiously into the culture medium when M1 was expressed by using the vaccinia virus T7 RNA polymerase-driven overexpression system, in our noncytotoxic VLP system M1 was not released efficiently into the culture medium. Additionally, hemagglutinin (HA), when treated with exogenous neuraminidase (NA) or coexpressed with viral NA, could be released from cells independently of M1. Incorporation of M1 into VLPs required HA expression, although when M1 was omitted from VLPs, particles with morphologies similar to those of wild-type VLPs or viruses were observed. Furthermore, when HA and NA cytoplasmic tail mutants were included in the VLPs, M1 failed to be efficiently incorporated into VLPs, consistent with a model in which the glycoproteins control virus budding by sorting to lipid raft microdomains and recruiting the internal viral core components. VLP formation also occurred independently of the function of Vps4 in the multivesicular body pathway, as dominant-negative Vps4 proteins failed to inhibit influenza VLP budding.
Adeno-Associated Virus Type 2 (AAV2) Capsid-Specific Cytotoxic T Lymphocytes Eliminate Only Vector-Transduced Cells Coexpressing the AAV2 Capsid In Vivo
Authors: Li Chengwen , Hirsch Matthew , Asokan Aravind , Zeithaml Brian , Ma Hong , Kafri Tal , Samulski R. Jude
Published: May 2007

A recent clinical trial has suggested that recombinant adeno-associated virus (rAAV) vector transduction in humans induces a cytotoxic T-lymphocyte (CTL) response against the AAV2 capsid. To directly address the ability of AAV capsid-specific CTLs to eliminate rAAV-transduced cells in vitro and in vivo in mice, we first demonstrated that AAV2 capsid-specific CTLs could be induced by dendritic cells with endogenous AAV2 capsid expression or pulsed with AAV2 vectors. These CTLs were able to kill a cell line stable for capsid expression in vitro and also in a mouse tumor xenograft model in vivo. Parent colon carcinoma (CT26) cells transduced with a large amount of AAV2 vectors in vitro were also destroyed by these CTLs. To determine the effect of CTLs on the elimination of target cells transduced by AAV2 vectors in vivo, we carried out adoptive transfer experiments. CTLs eliminated liver cells with endogenous AAV2 capsid expression but not liver cells transduced by AAV2 vectors, regardless of the reporter genes. Similar results were obtained for rAAV2 transduction in muscle. Our data strongly suggest that AAV vector-transduced cells are rarely eliminated by AAV2 capsid-specific CTLs in vivo, even though the AAV capsid can induce a CTL response. In conclusion, AAV capsid-specific CTLs do not appear to play a role in elimination of rAAV-transduced cells in a mouse model. In addition, our data suggest that the mouse model may not mimic the immune response noted in humans and additional modification to AAV vectors may be required for further study in order to elicit a similar cellular immune response.
Eunotiaspp. (Bacillariophyceae) from Middle Eocene lake sediments and comments on the origin of the diatom raphe
Authors: Siver Peter A. , Wolfe Alexander P.
Published: April 2007

Freshwater diatoms belonging to the genus Eunotia Ehrenberg 1837 are well preserved in Middle Eocene lake sediments from the Northwest Territories, Canada. Although two distinct valve morphologies are recognized, both have features that are entirely compatible with modern congeneric taxa, including dorsiventral valve morphology, striae spanning the valve face and extending onto the mantle, raphe structures on the mantle that extend distally onto the valve face, two helictoglossae per valve, and one apical rimoportula per valve. These findings establish that the genus Eunotia, and likely freshwater raphid diatoms as a whole, are more ancient than previously believed, dating back to at least 40 Ma. One of the observed morphotypes has a raphe spanning more than 80% of the valve length as well as a narrow hyaline area extending between proximal raphe endings and interrupting mantle striae. These features imply that the raphe system among certain ancient representatives of Eunotia was more developed relative to modern counterparts. The notion of progressive degeneration of the raphe within Eunotia is supported by several extant species. Collectively, these observations confirm molecular phylogenetic arguments that position Eunotia as a basal raphid diatom.
Sphagnum establishment and expansion in black spruce (Picea mariana) boreal forests
Authors: Fenton Nicole J. , Béland Catherine , De Blois Sylvie , Bergeron Yves
Published: April 2007

Boreal forest bryophyte communities are made up of distinct colonies of feathermosses that cover the forest floor. In some black spruce ( Picea mariana (Mill.) BSP) boreal forests, Sphagnum spp. establish colonies on the forest floor 30–40 years after the feathermosses, and ultimately expand to dominate the community. The mechanisms that permit the Sphagnum spp. to establish and expand are unknown. The objectives of this study were to examine the establishment and expansion substrates of Sphagnum spp., and the conditions correlated with colony expansion. Forty colonies, in six stands, of Sphagnum capillifolium (Ehrh.) Hedw. were dissected to determine their substrates, and the environmental conditions in which all colonies present were growing were measured. Coarse woody debris was the dominant establishment and early expansion substrate for Sphagnum capillifolium colonies. With age as the control factor, large colonies showed a significant partial correlation with canopy openness, and there were fewer individuals per cm3 in large colonies than there were in small colonies. These results suggest that Sphagnum establishment in these communities is dependent on the presence of coarse woody debris, and expansion is linked to the stand break-up, which would allow an increase in light intensity, and rainfall to reach the colony. Consequently the community change represented by Sphagnum establishment and expansion is initially governed by a stochastic process and ultimately by habitat availability and species competition.