bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rotifer species richness along an altitudinal gradient in the Alps
Authors: Obertegger Ulrike , Thaler Bertha , Flaim Giovanna 
Published: June 2010

ABSTRACTAim  Biodiversity patterns along altitudinal gradients are less studied in aquatic than terrestrial systems, even though aquatic sites provide a more homogeneous environment independent of moisture constraints. We studied the altitudinal species richness pattern for planktonic rotifers in freshwater lakes and identified the environmental predictors for which altitude is a proxy.Location  Two hundred and eighteen lakes of Trentino–South Tyrol (Italy) in the eastern Alps; lakes covered 98% (range 65–2960 m above sea level) of the altitudinal gradient in the Alps.Methods  We performed: (1) linear regression between species richness and altitude to evaluate the general pattern, (2) multiple linear regression between species richness and environmental predictors excluding altitude to identify the most important predictors, and (3) linear regression between the residuals of the best model of step (2) and altitude to investigate any additional explanatory power of altitude. Selection of environmental predictors was based on limnological importance and non‐parametric Spearman correlations. We applied ordinary least squares regression, generalized linear, and generalized least squares modelling to select the most statistically appropriate model.Results  Rotifer species richness showed a monotonic decrease with altitude independent of scale effects. Species richness could be explained (R2= 51%) by lake area as a proxy for habitat diversity, reactive silica and total phosphorus as proxies for productivity, water temperature as a proxy for energy, nitrate as a proxy for human influence and north–south and east–west directions as covariates. These predictors completely accounted for the species richness–altitude pattern, and altitude had no additional effect on species richness.Main conclusions  The linear decrease of species richness along the altitudinal gradient was related to the interplay of habitat diversity, productivity, heat content and human influence. These factors are the same in terrestrial and aquatic habitats, but the greater environmental stability of aquatic systems seems to favour a linear pattern.
The Medieval World View: Contemplating the Mappamundi
Authors: Edson Evelyn 
Published: June 2010

AbstractLooking at a medieval mappamundi (or world map) is a disorienting experience. Oriented to the east, displaying unfamiliar geographical forms and blanketed with images of strange animals and monstrous humans, it does not correspond to our modern concept of a world map. In the late 19th century scholars of the history of cartography dismissed medieval maps as a sign of ignorance. More recent studies have cast new light on these complex symbolic constructions, and scholars are searching for insights into medieval concepts of time and space, as well as clues to the ways in which knowledge of ancient geography was transmitted to the medieval intellectual world.
Oral squamous cell carcinoma and cultural oral risk habits in Vietnam
Authors: Priebe SL , Aleksejūnienė J , Zed C , Dharamsi S , Thinh DHQ , Hong NT , Cuc TTK , Thao NTP 
Published: June 2010

To cite this article:

Int J Dent Hygiene 8, 2010; 159–168 DOI: 10.1111/j.1601‐5037.2010.00461.x Priebe SL, Aleksejūnienė J, Zed C, Dharamsi S, Thinh DHQ, Hong NT, Cuc TTK, Thao NTP. Oral squamous cell carcinoma and cultural oral risk habits in Vietnam.Abstract:Objectives:  In South‐Central Asia, 80% of head and neck cancers are found in the oral cavity and oropharynx. In Vietnam, oral cancer is often not being detected until people experience debilitating circumstances to normal oral function. The aims of the study were to explore the patterns of oral squamous cell carcinoma (OSCC) and its risk indicators, the structure of oral health care in Vietnam and trends in prevalence of cultural risk habits in southern Vietnamese patients.Materials and Methods:  A retrospective clinical study was performed from 1 July 2005 to 1 April 2006 at Ho Chi Minh City Oncology hospital in Vietnam. Of the 161 cases, 147 subjects were diagnosed with OSCC, including 100 male and 47 female adults aged 24–85 years. Data were collected by a structured interview and clinical examination.Results:  Over 40% of the women with OSCC reported chewing betel quid and the most prevalent risk habit in males was smoking (91.0%). Daily alcohol use was reported by 79.0% of males and 2.1% of females. Two‐thirds of the cases of OSCC were diagnosed at the 2nd and 3rd stage of cancer. The more advanced stages of cancer were observed in males than in females. The prevalence of tobacco and alcohol use in males with OSCC was higher in this study than in the previous Vietnamese studies.Conclusion:  High frequency of risk habits in both genders was reported in OSCC Vietnamese patients. A trend of increased tobacco and alcohol use was observed in male OSCC patients. A lower prevalence of later staging in Vietnam was observed in this study than in earlier studies.
Up to D[eb]ate on Raising and Control Part 1: Properties and Analyses of the Constructions
Authors: Kirby Susannah , Davies William D. , Dubinsky Stanley 
Published: June 2010

AbstractThis is the first part of a two‐part article that reviews a number of the current debates regarding raising and control constructions. The issues addressed in this part include the syntactic attributes governing their distribution, the characterization of the relevant silent elements, and the empirical properties that may distinguish/unify the two classes of constructions (on either syntactic or semantic grounds).
Changing Spaces: Locating Public Space at the Intersection of the Physical and Digital
Authors: Alex de Freitas C. 
Published: June 2010

AbstractIt is widely held that the introduction of information communication technologies (ICTs) has resulted in significant changes to the organisation of cities, public spaces and everyday social life. Despite this, the extent and nature of these changes is something that is less than well established. This paper argues that conceptions of space and time have been radically altered by the new forms of accessibility and connectivity that are afforded by ICTs; in particular, wireless technologies, which continue to blur the boundaries between the public and private spaces of the city. The contemporary urban public spatial realm is neither physical nor digital, but an intricate and relational combination of the two. There is a need for a (re)conceptualisation of public space in light of this interconnection. Concepts such as ‘hybrid’ space might have been useful to some extent, but a fluid, less dualistic, more abstract mental image of public spaces is now required. The paper concludes that future research of urban public spaces must be situated in‐between the physical and digital and necessarily extend its scope beyond the traditional theoretical and methodological boundaries of the geographical discipline.
Aestheticizing Space: Art, Gentrification and the City
Authors: Mathews Vanessa 
Published: June 2010

AbstractThis article explores the relationship between art and gentrification at the urban scale. In particular, it maps shifting conceptualizations of this relationship through a focus on art, artists and arts spaces in the successive waves of gentrification. The first half of the article outlines the conceptualization of the arts in the first and second waves of gentrification, beginning with artist location preferences, detailing how and why these areas become attractive for higher income groups, and the agency prescribed to artists within the process. In the second half, the article places these findings in conversation with current debates taking place in the field surrounding third wave gentrification, in particular, how the arts are incorporated into public‐policy and urban regeneration with a focus on public art and arts infrastructure. The conclusion raises questions about how the incorporation of the arts in city programming complicates understandings of gentrification, and presents future avenues for research.
Registration‐based segmentation with articulated model from multipostural magnetic resonance images for hand bone motion animation
Authors: Chen Hsin‐Chen , Jou I‐Ming , Wang Chien‐Kuo , Su Fong‐Chin , Sun Yung‐Nien 
Published: June 2010

PurposeThe quantitative measurements of hand bones, including volume, surface, orientation, and position are essential in investigating hand kinematics. Moreover, within the measurement stage, bone segmentation is the most important step due to its certain influences on measuring accuracy. Since hand bones are small and tubular in shape, magnetic resonance (MR) imaging is prone to artifacts such as nonuniform intensity and fuzzy boundaries. Thus, greater detail is required for improving segmentation accuracy. The authors then propose using a novel registration‐based method on an articulated hand model to segment hand bones from multipostural MR images.MethodsThe proposed method consists of the model construction and registration‐based segmentation stages. Given a reference postural image, the first stage requires construction of a drivable reference model characterized by hand bone shapes, intensity patterns, and articulated joint mechanism. By applying the reference model to the second stage, the authors initially design a model‐based registration pursuant to intensity distribution similarity, MR bone intensity properties, and constraints of model geometry to align the reference model to target bone regions of the given postural image. The authors then refine the resulting surface to improve the superimposition between the registered reference model and target bone boundaries.ResultsFor each subject, given a reference postural image, the proposed method can automatically segment all hand bones from all other postural images. Compared to the ground truth from two experts, the resulting surface image had an average margin of error within 1 mm (mm) only. In addition, the proposed method showed good agreement on the overlap of bone segmentations by dice similarity coefficient and also demonstrated better segmentation results than conventional methods.ConclusionsThe proposed registration‐based segmentation method can successfully overcome drawbacks caused by inherent artifacts in MR images and obtain more accurate segmentation results automatically. Moreover, realistic hand motion animations can be generated based on the bone segmentation results. The proposed method is found helpful for understanding hand bone geometries in dynamic postures that can be used in simulating 3D hand motion through multipostural MR images.
On the insensitivity of single field planar dosimetry to IMRT inaccuracies
Authors: Kruse Jon J. 
Published: June 2010

PurposeTo report on the sensitivity of single field planar measurements in identifying IMRT plans with poor calculational accuracy.MethodsThree IMRT plans for head and neck cancer were subjected to extensive quality assurance. The plans were recalculated on a cylindrical phantom and between eight and 18 low gradient points were measured in each plan with an ion chamber. Every point measured in these plans agreed to within 4% of the dose predicted by the planning system and the plans were judged acceptable for clinical use. Each plan was then reoptimized with aggressive dose constraints so that the new treatment fields were more highly modulated than the ones from the original plans. Very complex fields can be calculated less accurately and ion chamber measurements of these plans in the cylindrical phantom confirmed significant dosimetric errors—Several of the measured points in each plan differed from the calculated dose by more than 4%, with a maximum single deviation of 10.6%. These three plans were judged unacceptable for clinical use. All six plans (three acceptable, three unacceptable) were then analyzed with two means of individual field planar dosimetry: Portal imaging with an electronic portal imaging device (EPID) and an ion chamber array. Gamma analysis was performed on each set of planar measurements with 2%/2 mm distance to agreement (DTA) and 3%/3 mm DTA criteria to try to determine a gamma analysis threshold which would differentiate the flawed plans from the acceptable ones.ResultsWith the EPID and 2%/2 mm DTA criteria, between 88.2% and 92.8% of pixels from the acceptable IMRT plans passed the gamma analysis, and between 87.5% and 91.9% passed for the unacceptable IMRT plans. With the ion chamber array and 2%/2 mm DTA criteria, between 92.4% and 94.9% of points in the acceptable plans passed the gamma analysis, while 86.8% to 98.3% of the points in the unacceptable plans passed the gamma analysis. The difference between acceptable and unacceptable plans was diminished further when gamma criteria were expanded to 3%/3 mm DTA. A fraction of pixels passing the gamma analysis was found to be a poor predictor of dosimetric accuracy with both planar dosimeters, as well as both sets of gamma criteria.ConclusionsDeconstruction of an IMRT plan for field‐by‐field QA requires complex analysis methods such as the gamma function. Distance to agreement, a component of the gamma function, has clinical relevance in a composite plan but when applied to individual, highly modulated fields, it can mask important dosimetric errors. While single field planar dosimetry may comprise one facet of an effective QA protocol, gamma analysis of single field measurements is insensitive to important dosimetric inaccuracies of the overall plan.
Significant dose can be lost by extended delivery times in IMRT with x rays but not high‐LET radiations
Authors: Joiner Michael C. , Mogili Nagaraju , Marples Brian , Burmeister Jay 
Published: June 2010

PurposeTo experimentally simulate IMRT delivery using two human cell modelsin vitro and test the hypothesis that a loss in effective dose resulting from the prolongation of megavoltage x‐ray treatment delivery time would be greatly reduced in corresponding IMRT simulations using higher‐LET radiation.MethodsThe effect of prolonging the delivery time of a treatment fraction was investigatedin vitro using human PC‐3 prostate and HGL21 glioblastoma tumor cell lines. Cells were irradiated with x rays from a conventional linear accelerator or with neutrons from a clinical radiotherapy beam and maintained at throughout. The delivery time for six closely spaced doses, simulating six multiple‐port segments, was varied from acute to 60 min for x‐ray irradiation, and acute to 120 min for neutron irradiation. Cell survival was measured following summed doses for the six segments of 0.5–6 Gy for x rays and 0.16–2 Gy for neutrons, covering the most likely range of dose per fraction used in clinical radiotherapy.ResultsProlonging x‐ray delivery time (from initiation of segment 1 to initiation of segment 6) from 5 to 45 min resulted in a loss in effective total dose (in equivalent 2 Gy multifraction treatments) of 5.6% in the PC‐3 cell line and 11.7% in the HGL21 cell line. More clinically common prolongations of 5–30 and 5–15 min resulted in effective dose reductions of 3.8% and 1.7% for PC‐3, and 7.3% and 2.9% for HGL21. A loss of less than 0.5% in effective dose was observed for prolongations up to 45 min of similarly effective neutron irradiation of PC‐3 and HGL21 cells.ConclusionsProlonged delivery times of photon fractions could have a significant impact on treatment outcome especially for tumors with a low ratio and short repair halftime. These effects are significant at delivery times commonly associated with IMRT and are variable with cell type. X‐ray IMRT should therefore always be planned to minimize dose‐fraction delivery time. However, if IMRT treatments are delivered with high‐LET radiation, this considerably reduces the dependence of the biological effect on fraction delivery time even out to 2 h.
A method to correct the influence of carbon fiber couchtop and patient positioning device on image quality of cone beam CT
Authors: Men Kuo , Dai Jianrong , Li Minghui , Zhang Yin 
Published: June 2010

PurposeTo evaluate the influence of carbon fiber couchtop and patient positioning devices on cone beam CT (CBCT) image quality and develop an effective method to correct the influence.MethodsA standard CT phantom (Catphan 500) was used to evaluate the influence of iBeam evo carbon fiber couchtop on the quality of CBCT image obtained from an Elekta synergy machine. The evaluation indices were contrast‐to‐noise ratio (CNR), spatial resolution, image uniformity, and image noise. With using the Beer–Lambert law and the energy‐response function of the flat‐panel imager, a method was applied to deduct the image signal of the couchtop (and the positioning devices) from each projection image of a phantom/patient, and then used all corrected projection images to reconstruct a CBCT image. The performance of the correction method was evaluated using the CBCT images of a Catphan 500 phantom, a head‐and‐neck cancer patient, and a prostate cancer patient.ResultsIn two phantom studies (the phantom to simulate a human head and neck and the one to simulate a human body), the CNR of the CBCT images obtained with the couchtop reduced 18.1% and 29.8%, respectively with respect to those obtained without the couchtop; meanwhile, the image uniformity reduced 16.4% and 24.1% due to the use of the carbon fiber couchtop. The couchtop also induced extra image noise (16.5% for the h&n phantom and 4.2% for the body phantom). However, CBCT imaging with the couchtop did not affect the spatial resolution. After applying the projection image correction, there was a significant improvement in CNR (by 19.5% and 25.8%), image uniformity (by 9.2% and 13.1%), and image noise (by 10.2% and 3.9%), with respect to CBCT images obtained with the couchtop.ConclusionsThe presence of the carbon fiber couchtop and the patient positioning devices can significantly impair CBCT image quality in terms of the CNR, the image uniformity, and the image noise. By removing the influence of the couchtop and the patient‐positioning devices from CB projection images, the correction method improves CBCT image quality and thus image guidance in radiotherapy.
Dose correction strategy for the optimization of volumetric modulated arc therapya)
Authors: Zhang Pengpeng , Yang Jie , Hunt Margie , Mageras Gig 
Published: June 2010

PurposeDose calculation during optimization of volumetric modulated arc therapy (VMAT) is necessarily simplified to keep computation time manageably low; however the approximations used in the scatter dose calculation lead to discrepancy with more accurate dose calculation following optimization. The purpose of this study is to develop a dose correction strategy in optimization that can minimize the disagreement.MethodsVMAT delivery is modeled using a number of static equispaced beams. Dose correction factors are associated with each beam and point inside the region of interest. is calculated as the ratio of dose obtained from the full scatter dose calculation over that from the partial scatter dose calculation in optimization. VMAT optimization algorithm is a multiple resolution approach. The dose correction factors are calculated at the beginning of each resolution and applied as multiplicative corrections to the partial scatter dose during optimization. Clinical cases for brain, prostate, paraspinal, and esophagus are utilized to evaluate the method. Treatment plans created with and without the correction scheme are normalized such that the complication rates of organs at risk (OARs) are comparable. The resulting planning target volume (PTV) mean doses are used to compare plan quality.ResultsThe difference between the dose calculated at the end of optimization and at the end of the final forward dose calculation is reduced from 7% and 5% for the PTV and OAR mean doses without correction to approximately 1% with correction. Applying dose correction during optimization saves planners 2–4 h in average in treatment planning, and has a positive impact on plan quality, evidenced by a noticeably higher PTV mean dose: 2.1%, 2.4%, 0.5%, and 9.3% of the corresponding prescription dose in the brain, esophagus, prostate, and paraspinal cases, respectively.ConclusionsWhen dose correction is applied during optimization, dose discrepancies between optimization and full dose calculation are reduced. Integrating dose correction in VMAT optimization allows planners to adjust the optimization constraints more easily and confidently during optimization and has the potential to improve plan quality.
Age‐ and race‐dependence of the fibroglandular breast density analyzed on 3D MRI
Authors: Nie Ke , Su Min‐Ying , Chau Man‐Kwun , Chan Siwa , Nguyen Hoanglong , Tseng Tiffany , Huang Yuhong , McLaren Christine E. , Nalcioglu Orhan , Chen Jeon‐Hor 
Published: June 2010

PurposeThe purpose of this study was to evaluate the age‐ and race‐dependence of the breast fibroglandular tissue density based on three‐dimensional breast MRI.MethodsThe normal breasts of 321 consecutive patients including Caucasians, Asians, and Hispanics were studied. The subjects were separated into three age groups: Younger than 45, between 45 and 55, and older than 55. Computer algorithms based on body landmarks were used to segment the breast, and fuzzy c‐means algorithm was used to segment the fibroglandular tissue. Linear regression analysis was applied to compare mean differences among different age groups and race/ethnicity groups. The obtained parameters were not normally distributed, and the transformed data, natural log (ln) for the fibroglandular tissue volume, and the square root for the percent density were used for statistical analysis.ResultsOn the average, the transformed fibroglandular tissue volume and percent density decreased significantly with age. Racial differences in mean transformed percent density were found among women older than 45, but not among women younger than 45. Mean percent density was higher in Asians compared to Caucasians and Hispanics; the difference remained significant after adjustment for age, but not significant after adjusted for both age and breast volume. There was no significant difference in the density between the Caucasians and the Hispanics.ConclusionsThe results analyzed using the MRI‐based method show age‐ and race‐dependence, which is consistent with literature using mammography‐based methods.