bluuebunny/crossref_metadata_2025 huggingface dataset:
Fluorescence Spectra and Images of Latent Fingerprints Excited with a Tunable Laser in the Ultraviolet Region
Authors: Akiba Norimitsu , Saitoh Naoki , Kuroki Kenro
Published: August 2007

Fluorescence spectra of sebum‐rich latent fingerprints were studied with a tunable laser for non‐destructive fingerprint detection without chemical treatment. The tunable laser consists of a nanosecond pulsed Nd‐YAG laser and an optical parametric oscillator (OPO) crystal. The fluorescence spectra and images were measured at various excitation wavelengths in the ultraviolet region by the time‐resolved fluorescence method. We have previously reported that a typical fluorescence spectrum of fingerprints consists of two peaks located atc.330 and 440 nm. In order to determine the wavelength of optimal excitation, excitation spectra were measured at wavelengths ranging from 220 to 310 nm. The fluorescence intensity of the 330 nm peak became maximal with excitation at 280 nm. The images of latent fingerprints on white papers were also measured and the clearest image was obtained with excitation at 280 nm. The influence of continuous irradiation on the fluorescence of fingerprints was measured at the optimal excitation wavelengths. The 330 nm peak was strong at first and decreased with continuous irradiation, whereas the 440 nm peak, which was weak at first, increased gradually.
Characterization of the Variant Allele 9.2 of Penta D Locus*
Authors: Miozzo María C. , Maxzud Mariana K. , Pacharoni Carla M. , Mutal Silvia A. , Modesti Nidia M.
Published: August 2007

DNA profiles of forensic cases of Córdoba Province, Argentina, typed by PowerPlex® 16 kit (Promega), have shown in the Penta D locus few samples with a variant allele migrating as an off ladder between alleles 9 and 10. In order to determine the molecular basis of the new variant allele, three samples were subject to polymerase chain reaction amplification of the Penta D locus by monoplex, and were further purified and sequenced. The sequence analysis revealed that the off ladder allele has ten repeats motifs AAAGA as allele 10, with three nucleotides (TAA) deletion in the 3′ flanking region, 128 nucleotides after the last repeat. Therefore, the variant allele could be explained by a deletion of allele 10, and was designated 9.2. Mse I digestion assay allows to corroborate allele 9.2 without sequencing. A population study in Córdoba Province indicates that allele 9.2 of Penta D locus has a frequency of 0.0063.
Cardiovascular Risk With Subclinical Hyperthyroidism and Hypothyroidism: Pathophysiology and Management
Authors: Duggal Jasleen , Singh Sarabjeet , Barsano Charles P. , Arora Rohit
Published: September 2007

Previous studies have suggested that subclinical thyroid dysfunction, as manifested by abnormalities in thyroid‐stimulating hormone (TSH) levels, are associated with detrimental effects on the cardiovascular system. Subclinical hypothyroidism is characterized by abnormal lipid metabolism, cardiac dysfunction, diastolic hypertension conferring an elevated risk of atherosclerosis, and ischemic heart disease. Similarly, patients with subclinical hyperthyroidism have nearly 3 times the likelihood of atrial fibrillation over a 10‐year follow‐up interval, raising the question of whether patients with subclinical hyperthyroidism should be treated to prevent atrial fibrillation. A single measurement of low serum TSH in individuals aged 60 years or older has been reported to be associated with increased mortality from all causes and in particular from circulatory and cardiovascular disease in a 10‐year follow‐up study. Subclinical thyroid dysfunction is currently the subject of numerous studies and remains controversial, particularly as it relates to cardiovascular morbidity and mortality and clinical applications.
Visual outcome and cataract development after allogeneic stem‐cell transplantation in children
Authors: Fahnehjelm Kristina Teär , Törnquist Alba‐Lucia , Olsson Monica , Winiarski Jacek
Published: August 2007

Purpose:  To report visual functions and prevalence of cataract after haematopoetic stem‐cell transplantation (SCT) during childhood and to determine the impact of different conditioning regimes and other possible risk factors.

Methods:  Assessment of visual acuity (VA), slit‐lamp biomicroscopy of the lenses and examination of the ocular fundii were performed in 79 subjects 2–18 years (median 7 years) after SCT.

Results:  Best‐corrected decimal VA ≥ 0.5 was achieved in 152/158 eyes (96%). There was an increased risk of cataract after conditioning with single‐dose total body irradiation (s‐TBI) or fractionated TBI (f‐TBI) compared to busulfan or other chemotherapy (P < 0.001) and an increased risk of developing cataract earlier if treated with s‐TBI compared to f‐TBI (P < 0.01). The TBI mode did not affect the time to first surgical intervention. Apart from s‐TBI and f‐TBI, age was found to be an independent risk factor. Cataract also developed in patients prepared with chemotherapy but no patient required surgery. Neither treatment with steroids for 6 months or longer nor history of chronic graft versus host disease (GVHD) influenced cataract development.

Conclusion:  Conditioning with full dose f‐TBI compared to s‐TBI postpones but does not prevent cataract or cataract surgery while chemotherapy‐based conditioning induces less severe cataracts, usually not requiring surgery. Corticosteroids or GVHD do not appear as risk factors.
A Polypodium leucotomos extract inhibits solar‐simulated radiation‐induced TNF‐α and iNOS expression, transcriptional activation and apoptosis
Authors: Jańczyk Agnieska , Garcia‐Lopez Mª Angeles , Fernandez‐Peñas Pablo , Alonso‐Lebrero Jose Luis , Benedicto Ignacio , López‐Cabrera Manuel , Gonzalez Salvador
Published: August 2007

Abstract:  In this report, we have examined the molecular basis of the photoprotective effect of a hydrophilic extract of the fern Polypodium leucotomos (PL) in vitro, using a solar simulator as the source of UV radiation (SSR). We found that pretreatment of human keratinocytes with PL inhibited SSR‐mediated increase of tumor necrosis factor (TNF)‐α and also abrogated nitric oxide (NO) production. Consistent with this, PL blocked the induction of inducible nitric oxide synthase (iNOS) elicited by SSR. In addition, PL inhibited the SSR‐mediated transcriptional activation of NF‐κB and AP1. Finally, we demonstrated that pretreatment with PL exerted a cytoprotective effect against SSR‐induced damage, resulting in increased cell survival. Together, these data postulate a multifactor mechanism of protection not exclusively reliant on the antioxidant capability of PL, and strengthen the basic knowledge on the photoprotective effect of this botanical agent.
Anti‐wrinkling effects of the mixture of vitamin C, vitamin E, pycnogenol and evening primrose oil, and molecular mechanisms on hairless mouse skin caused by chronic ultraviolet B irradiation
Authors: Cho Ho‐Song , Lee Min‐Ho , Lee Jae Woong , No Kyong‐Ok , Park Sang‐Ki , Lee Heon‐Sik , Kang Sangjin , Cho Wan‐Goo , Park Hye Ji , Oh Ki Wan , Hong Jin Tae
Published: September 2007

Background: Naturally occurring antioxidants were used to regulate the skin damage caused by ultraviolet (UV) radiation because several antioxidants have demonstrated that they can inhibit wrinkle formation through prevention of matrix metalloproteinases (MMPs) and/or increase of collagen synthesis.

Objective: We examined the effect of oral administration of the antioxidant mixture of vitamin C, vitamin E, pycnogenol, and evening primrose oil on UVB‐induced wrinkle formation. In addition, we investigated the possible molecular mechanism of photoprotection against UVB through inhibition of collagen‐degrading MMP activity or through enhancement of procollagen synthesis in mouse dorsal skin.

Methods: Female SKH‐1 hairless mice were orally administrated the antioxidant mixture (test group) or vehicle (control group) for 10 weeks with UVB irradiation three times a week. The intensity of irradiation was gradually increased from 30 to 180 mJ/cm2. Microtopographic and histological assessment of the dorsal skins was carried out at the end of 10 weeks to evaluate wrinkle formation. Western blot analysis and EMSA were also carried out to investigate the changes in the balance of collagen synthesis and collagen degradation.

Results: Our antioxidant mixture significantly reduced UVB‐induced wrinkle formation, accompanied by significant reduction of epidermal thickness, and UVB‐induced hyperplasia, acanthosis, and hyperkeratosis. This antioxidant mixture significantly prevented the UVB‐induced expressions of MMPs, mitogen‐activated protein (MAP) kinase, and activation of activator protein (AP)‐1 transcriptional factor in addition to enhanced type I procollagen and transforming growth factor‐β2 (TGF‐β2) expression.

Conclusion: Oral administration of the antioxidant mixture significantly inhibited wrinkle formation caused by chronic UVB irradiation through significant inhibition of UVB‐induced MMP activity accompanied by enhancement of collagen synthesis.
Ammonium chloride and l‐tyrosine enhance melanogenesis in vitro but not in vivo even in combination with ultraviolet radiation
Authors: Kongshoj Brian , Dam Mikkelsen Nikolaj , Kobayasi Takasi , Lerche Catharina Margrethe , Wulf Hans Christian
Published: September 2007

Background/Purpose: Melanogenesis can be induced in vitro in melanoma cells and melanocytes by adding substances able to neutralize intracellular acidic organelles like melanosomes. Further addition of l‐tyrosine enhances the melanogenesis by increasing the tyrosinase activity. As such, the property of tyrosine as a pigmentation enhancer is used in promoting creams containing tyrosine. The objective of this study was to investigate whether such an effect could actually be seen in a short term in vivo mouse study.

Methods: Lightly pigmented C3.Cg/TifBomTac hairless mice capable of pigmenting had ammonium chloride (NH4Cl) and/or l‐tyrosine applied topically (1/day for 3 weeks). Pigmentation of the mice was determined using the Kodak Gray Scale at days 0, 7, 14, and 21.

Results: Both NH4Cl and l‐tyrosine yielded no significant effect, either alone or in combination, when applied using either hydrogel or moisturizing cream. Exposing mice to simulated solar radiation (4 standard erythema doses, 3/week) yielded increased pigmentation. However, no statistically significant difference was found between treatment with simulated solar radiation alone or in combination with NH4Cl and l‐tyrosine.

Conclusion: In spite of the commercial value of adding l‐tyrosine to ‘pigmentation‐enhancing’ creams, topically applied l‐tyrosine showed no pigmentation‐enhancing effect, neither alone nor in combination with ultraviolet (UV) radiation, providing a basis to contest such promotional measures.
Basic Emotions, Natural Kinds, Emotion Schemas, and a New Paradigm
Authors: Izard Carroll E.
Published: September 2007

Research on emotion flourishes in many disciplines and specialties, yet experts cannot agree on its definition. Theorists and researchers use the term emotion in ways that imply different processes and meanings. Debate continues about the nature of emotions, their functions, their relations to broad affective dimensions, the processes that activate them, and their role in our daily activities and pursuits. I will address these issues here, specifically in terms of basic emotions as natural kinds, the nature of emotion schemas, the development of emotion—cognition relations that lead to emotion schemas, and discrete emotions in relation to affective dimensions. Finally, I propose a new paradigm that assumes continual emotion as a factor in organizing consciousness and as an influence on mind and behavior. The evidence reviewed suggests that a theory that builds on concepts of both basic emotions and emotion schemas provides a viable research tool and is compatible with more holistic or dimensional approaches.
Neurologizing the Psychology of Affects: How Appraisal-Based Constructivism and Basic Emotion Theory Can Coexist
Authors: Panksepp Jaak
Published: September 2007

Abundant neurobehavioral data, not discussed by Lisa Feldman Barrett (2006) , support the existence of a variety of core emotional operating systems in ancient subneocortical regions of the brain ( Panksepp, 1998a , 2005a ). Such brain systems are the primary-process ancestral birthrights of all mammals. There may be as many genetically and neurochemically coded subcortical affect systems in emotionally rich medial regions of the brain as there are “natural” emotional action systems in the brain. When emotional primes are aroused directly, as with local electrical or chemical stimulation, the affective changes sustain conditioned place preferences and place aversions, which are the premier secondary-process indices of affective states in animals. Humans are not immune to such brain manipulations; they typically exhibit strong emotional feelings. Human emotion researchers should not ignore these systems and simply look at the complex and highly variable culturally molded manifestations of emotions in humans if they wish to determine what kinds of “natural” emotional processes exist within all mammalian brain. Basic emotion science has generated workable epistemological strategies for under-standing the primal sources of human emotional feelings by detailed study of emotional circuits in our fellow animals.
A Hydrologic/Water Quality Model Applicati11
Authors: Engel Bernard , Storm Dan , White Mike , Arnold Jeff , Arabi Mazdak
Published: September 2007

Abstract:  This paper presents a procedure for standard application of hydrologic/water quality models. To date, most hydrologic/water quality modeling projects and studies have not utilized formal protocols, but rather have employed ad hoc approaches. The procedure proposed is an adaptation and extension of steps identified from relevant literature including guidance provided by the U.S. Environmental Protection Agency. This protocol provides guidance for establishing written plans prior to conducting modeling efforts. Eleven issues that should be addressed in model application plans were identified and discussed in the context of hydrologic/water quality studies. A graded approach for selection of the level of documentation for each item was suggested. The creation and use of environmental modeling plans is increasingly important as the results of modeling projects are used in decision‐making processes that have significant implications. Standard modeling application protocols similar to the proposed procedure herein provide modelers with a roadmap to be followed, reduces modelers’ bias, enhances the reproducibility of model application studies, and eventually improves acceptance of modeling outcomes.
Enhancing Hyrdological Simulation Program – FORTRAN Model Channel Hydraulic Representation1
Authors: Mohamoud Yusuf M.
Published: September 2007

Abstract:  The hydrological simulation program – FORTRAN (HSPF) is a comprehensive watershed model that employs depth‐area‐volume‐flow relationships known as the hydraulic function table (FTABLE) to represent the hydraulic characteristics of stream channel cross‐sections and reservoirs. An accurate FTABLE determination for a stream cross‐section site requires an accurate determination of mean flow depth, mean flow width, roughness coefficient, longitudinal bed slope, and length of stream reach. A method that uses regional regression equations to estimate mean flow depth, mean flow width, and roughness coefficient is presented herein. FTABLES generated by the proposed method (Alternative Method) and FTABLES generated by Better Assessment Science Integrating Point and Nonpoint Sources (BASINS) were compared. As a result, the Alternative Method was judged to be an enhancement over the BASINS method. First, the Alternative Method employs a spatially variable roughness coefficient, whereas BASINS employs an arbitrarily selected spatially uniform roughness coefficient. Second, the Alternative Method uses mean flow width and mean flow depth estimated from regional regression equations whereas BASINS uses mean flow width and depth extracted from the National Hydrography Dataset (NHD). Third, the Alternative Method offers an option to use separate roughness coefficients for the in‐channel and floodplain sections of compound channels. Fourth, the Alternative Method has higher resolution in the sense that area, volume, and flow data are calculated at smaller depth intervals than the BASINS method. To test whether the Alternative Method enhances channel hydraulic representation over the BASINS method, comparisons of observed and simulated streamflow, flow velocity, and suspended sediment were made for four test watersheds. These comparisons revealed that the method used to estimate the FTABLE has little influence on hydrologic calibration, but greatly influences hydraulic and suspended sediment calibration. The hydrologic calibration results showed that observed versus simulated daily streamflow comparisons had Nash‐Sutcliffe efficiencies ranging from 0.50 to 0.61 and monthly comparisons had efficiencies ranging from 0.61 to 0.84. Comparisons of observed and simulated suspended sediments concentrations had model efficiencies ranging from 0.48 to 0.56 for the daily, and 0.28 to 0.70 for the monthly comparisons. The overall results of the hydrological, hydraulic, and suspended sediment concentration comparisons show that the Alternative Method yielded a relatively more accurate FTABLE than the BASINS method. This study concludes that hydraulic calibration enhances suspended sediment simulation performance, but even greater improvement in suspended sediment calibration can be achieved when hydrological simulation performance is improved. Any improvements in hydrological simulation performance are subject to improvements in the temporal and spatial representation of the precipitation data.
Adequacy of Visually Classified Particle Count Statistics From Regional Stream Habitat Surveys1
Authors: Faustini John M. , Kaufmann Philip R.
Published: September 2007

Abstract:  Streamlined sampling procedures must be used to achieve a sufficient sample size with limited resources in studies undertaken to evaluate habitat status and potential management‐related habitat degradation at a regional scale. At the same time, these sampling procedures must achieve sufficient precision to answer science and policy‐relevant questions with an acceptable and statistically quantifiable level of uncertainty. In this paper, we examine precision and sources of error in streambed substrate characterization using data from the Environmental Monitoring and Assessment Program (EMAP) of the U.S. Environmental Protection Agency, which uses a modified “pebble count” method in which particle sizes are visually estimated rather than measured. While the coarse (2ϕ) size classes used in EMAP have little effect on the precision of estimated geometric mean (Dgm) or median (D50) particle diameter, variable classification bias among observers can contribute as much as 0.3ϕ, or about 15‐20%, to the root‐mean‐square error (RMSE) of Dgm or D50 estimates. Dgm and D50 estimates based on EMAP data are nearly equal when fine sediments (<2 mm) are excluded, but otherwise can differ by up to a factor of 2 or more, with Dgm < D50 for gravel‐bed streams. The RMSE of reach‐scale particle size estimates based on visually classified particle count data from EMAP surveys, including variability associated with reoccupying unmarked sample reaches during revisits, is up to five to seven times higher than that reported for traditional measured pebble counts by multiple observers at a plot scale. Nonetheless, a variance partitioning analysis shows that the ratio of among site to revisit variance for several EMAP substrate metrics exceeds 8 for many potential regions of interest, suggesting that the data have adequate precision to be useful in regional assessments of channel morphology, habitat quality, or ecological condition.
Dominant species constrain effects of species diversity on temporal variability in biomass production of tallgrass prairie
Authors: Wayne Polley H. , Wilsey Brian J. , Derner Justin D.
Published: August 2007

Species diversity is thought to stabilize functioning of plant communities. An alternative view is that stability depends more on dynamics of dominant species than on diversity. We compared inter‐annual variability (inverse of stability) of aboveground biomass in paired restored and remnant tallgrass prairies at two locations in central Texas, USA. Data from these two locations were used to test the hypothesis that greater richness and evenness in remnant than restored prairies would reduce variability in aboveground biomass in response to natural variation in rainfall. Restored prairies were chosen to be similar to paired remnant prairies in characteristics other than species diversity that affect temporal variability in biomass. Variability was measured as the coefficient of variation among years (square root of variance/mean; CV), where variance in community biomass equals the sum of variances of individual plant species plus the summed covariances between species pairs. Species diversity over five years was greater by a factor of 2 or more in remnant than restored prairies because richness and evenness were greater in remnant than restored prairies. Still, the CV of community biomass during spring and CV of annual biomass production did not differ consistently between prairie types. Neither the sum of species covariances nor total community biomass differed between prairies. Biomass varied relatively little in restored compared to remnant prairies because biomass of the dominant species in restored prairies (the grassSchizachyrium scoparium) varied less than did biomass of other dominant and sub‐dominant species. In these grasslands, biomass response to natural variation in precipitation depended as much on characteristics of a dominant grass as on differences in diversity.
A reassessment of equivalence in yield from marine reserves and traditional fisheries managament
Authors: White Crow , Kendall Bruce E.
Published: August 2007

Lively debate continues over whether marine reserves can lead to increased fishery yields when compared to conventional, quota‐based management, apparently driven by differences in the complexity and biological richness of the models being used. In an influential article, Hastings and Botsford used an analytically tractable, spatially implicit, non‐age‐structured model to assert that reserves are typically incapable of increasing yields relative to conventional management, regardless of the type (pre‐ or post‐dispersal, involving adults and/or larvae) or functional form (Ricker or Beverton‐Holt) of density dependence present. A recent numerical (simulation) model by Gaylord et al. concludes that reserves can enhance yield compared to conventional management, a result the authors attribute to their spatially‐explicit evaluation of stage‐structured adult growth, survivability and fecundity; and intercohort (adult‐on‐larvae) post‐dispersal density dependent population dynamics. Here we demonstrate that the increased model complexity is not responsible for the different conclusions. We analyze a spatially‐implicit model without stage structure that incorporates intercohort post‐dispersal density dependence. In this simple model we still find annual extirpation of adult populations outside reserves due to fishing to enhance larval recruitment there, allowing for increased yields compared to those achieved when harvest is evenly spread across the entire domain under conventional management. Consideration of neither spatially‐explicit dispersal dynamics nor stage‐structure in adult demographics is required for reserves to substantially improve yield beyond that attainable under conventional management. In contrast, consideration of within cohort post‐dispersal density dependence among larva during settlement in an otherwise identical model generates equivalence in yield between the two management strategies. These results recast a common message characterizing the relative benefit of reserve versus non‐reserve management from “equivalence at best” to “potentially improved”.
Disentangling community patterns of nestedness and species co‐occurrence
Authors: Ulrich Werner , J. Gotelli Nicholas
Published: August 2007

Two opposing patterns of meta‐community organization are nestedness and negative species co‐occurrence. Both patterns can be quantified with metrics that are applied to presence‐absence matrices and tested with null model analysis. Previous meta‐analyses have given conflicting results, with the same set of matrices apparently showing high nestedness (Wright et al. 1998) and negative species co‐occurrence (Gotelli and McCabe 2002). We clarified the relationship between nestedness and co‐occurrence by creating random matrices, altering them systematically to increase or decrease the degree of nestedness or co‐occurrence, and then testing the resulting patterns with null models. Species co‐occurrence is related to the degree of nestedness, but the sign of the relationship depends on how the test matrices were created. Low‐fill matrices created by simple, uniform sampling generate negative correlations between nestedness and co‐occurrence: negative species co‐occurrence is associated with disordered matrices. However, high‐fill matrices created by passive sampling generate the opposite pattern: negative species co‐occurrence is associated with highly nested matrices. The patterns depend on which index of species co‐occurrence is used, and they are not symmetric: systematic changes in the co‐occurrence structure of a matrix are only weakly associated with changes in the pattern of nestedness. In all analyses, the fixed‐fixed null model that preserves matrix row and column totals has lower type I and type II error probabilities than an equiprobable null model that relaxes row and column totals. The latter model is part of the popular nestedness temperature calculator, which detects nestedness too frequently in random matrices (type I statistical error). When compared to a valid null model, a matrix with negative species co‐occurrence may be either highly nested or disordered, depending on the biological processes that determine row totals (number of species occurrences) and column totals (number of species per site).
De‐phosphorylation of MyoD is linking nerve‐evoked activity to fast myosin heavy chain expression in rodent adult skeletal muscle
Authors: Ekmark Merete , Rana Zaheer Ahmad , Stewart Greg , Hardie D. Grahame , Gundersen Kristian
Published: August 2007

Elucidating the molecular pathways linking electrical activity to gene expression is necessary for understanding the effects of exercise on muscle. Fast muscles express higher levels of MyoD and lower levels of myogenin than slow muscles, and we have previously linked myogenin to expression of oxidative enzymes. We here report that in slow muscles, compared with fast, 6 times as much of the MyoD is in an inactive form phosphorylated at T115. In fast muscles, 10 h of slow electrical stimulation had no effect on the total MyoD protein level, but the fraction of phosphorylated MyoD was increased 4‐fold. Longer stimulation also decreased the total level of MyoD mRNA and protein, while the level of myogenin protein was increased. Fast patterned stimulation did not have any of these effects. Overexpression of wild type MyoD had variable effects in active slow muscles, but increased expression of fast myosin heavy chain in denervated muscles. In normally active soleus muscles, MyoD mutated at T115 (but not at S200) increased the number of fibres containing fast myosin from 50% to 85% in mice and from 13% to 62% in rats. These data establish de‐phosphorylated active MyoD as a link between the pattern of electrical activity and fast fibre type in adult muscles.
A neural network model to predict lung radiation‐induced pneumonitis
Authors: Chen Shifeng , Zhou Sumin , Zhang Junan , Yin Fang‐Fang , Marks Lawrence B. , Das Shiva K.
Published: September 2007

A feed‐forward neural network was investigated to predict the occurrence of lung radiation‐induced Grade pneumonitis. The database consisted of 235 patients with lung cancer treated using radiotherapy, of whom 34 were diagnosed with Grade pneumonitis at follow‐up. The network was constructed using an algorithm that alternately grew and pruned it, starting from the smallest possible network, until a satisfactory solution was found. The weights and biases of the network were computed using the error back‐propagation approach. Momentum and variable leaning techniques were used to speed convergence. Using the growing/pruning approach, the network selected features from 66 dose and 27 non‐dose variables. During network training, the 235 patients were randomly split into ten groups of approximately equal size. Eight groups were used to train the network, one group was used for early stopping training to prevent overfitting, and the remaining group was used as a test to measure the generalization capability of the network (cross‐validation). Using this methodology, each of the ten groups was considered, in turn, as the test group (ten‐fold cross‐validation). For the optimized network constructed with input features selected from dose and non‐dose variables, the area under the receiver operating characteristics (ROC) curve for cross‐validated testing was 0.76 (sensitivity: 0.68, specificity: 0.69). For the optimized network constructed with input features selected only from dose variables, the area under the ROC curve for cross‐validation was 0.67 (sensitivity: 0.53, specificity: 0.69). The difference between these two areas was statistically significant , indicating that the addition of non‐dose features can significantly improve the generalization capability of the network. A network for prospective testing was constructed with input features selected from dose and non‐dose variables (all data were used for training). The optimized network architecture consisted of six input nodes (features), four hidden nodes, and one output node. The six input features were: lung volume receiving , generalized equivalent uniform dose (gEUD) for the exponent (mean lung dose), gEUD for the exponent , free expiratory volume in , diffusion capacity of carbon monoxide (DLCO%), and whether or not the patient underwent chemotherapy prior to radiotherapy. The significance of each input feature was individually evaluated by omitting it during network training and gauging its impact by the consequent deterioration in cross‐validated ROC area. With the exception of FEV1 and whether or not the patient underwent chemotherapy prior to radiotherapy, all input features were found to be individually significant . The network for prospective testing is publicly available via internet access.
Out‐of‐field dose equivalents delivered by proton therapy of prostate cancer
Authors: Wroe Andrew , Rosenfeld Anatoly , Schulte Reinhard
Published: September 2007

Measurements were performed to assess the dose equivalent outside a primary proton treatment field, using a silicon‐on‐insulator (SOI) microdosimeter. The SOI microdosimeter was placed on the surface of an anthropomorphic phantom and dose equivalents were determined as a function of lateral distance from a typical passively scattered and modulated prostate treatment field. Measurements were also completed within a polystyrene plate phantom as a function of depth for a distance of 5 cm from the field edge, as function of lateral distance from field edge at two different depths, and as a function of distance from the distal edge on the central beam axis. The dose equivalent at the surface of the anthropomorphic phantom decreases from 3.9 to 0.18 mSv/Gy when the lateral distance from the proton field edge increases from 2.5 to 60 cm. Measurements along the proton depth dose distribution at a constant distance of 5 cm from the primary field edge indicate a decrease in dose equivalent as a function of depth, with a decrease relative to the surface dose at a depth of 5 cm in polystyrene. Measurements completed as a function of lateral distance from the primary field at two separate depths within polystyrene illustrate a convergence of the dose equivalent at approximately 20 cm from the primary field edge. Past the distal edge of the spread‐out Bragg peak dose equivalents decrease exponentially for increasing distance, with an initial value of 1.6 mSv/Gy at 0.6 cm from the distal edge. Silicon microdosimetry measurements were also compared with published results obtained utilizing different measurement techniques. This study demonstrates the applicability of SOI microdosimetry in determining the dose equivalent outside proton treatment fields, and provides valuable information on the dose equivalent both at the surface and at depth experienced by prostate cancer patients treated with protons.
The effect of respiratory cycle and radiation beam‐on timing on the dose distribution of free‐breathing breast treatment using dynamic IMRT
Authors: Ding Chuxiong , Li Xiang , Huq M. Saiful , Saw Cheng B. , Heron Dwight E. , Yue Ning J.
Published: September 2007

In breast cancer treatment, intensity‐modulated radiation therapy (IMRT) can be utilized to deliver more homogeneous dose to target tissues to minimize the cosmetic impact. We have investigated the effect of the respiratory cycle and radiation beam‐on timing on the dose distribution in free‐breathing dynamic breast IMRT treatment. Six patients with early stage cancer of the left breast were included in this study. A helical computed tomography (CT) scan was acquired for treatment planning. A four‐dimensional computed tomography (4D CT) scan was obtained right after the helical CT scan with little or no setup uncertainty to simulate patient respiratory motion. After optimizing based on the helical CT scan, the sliding‐window dynamic multileaf collimator (DMLC) leaf sequence was segmented into multiple sections that corresponded to various respiratory phases per respiratory cycle and radiation beam‐on timing. The segmented DMLC leaf sections were grouped according to respiratory phases and superimposed over the radiation fields of corresponding 4D CT image set. Dose calculation was then performed for each phase of the 4D CT scan. The total dose distribution was computed by accumulating the contribution of dose from each phase to every voxel in the region of interest. This was tracked by a deformable registration program throughout all of the respiratory phases of the 4D CT scan. A dose heterogeneity index, defined as the ratio between and the prescription dose, was introduced to numerically illustrate the impact of respiratory motion on the dose distribution of treatment volume. A respiratory cycle range of and randomly distributed beam‐on timing were assigned to simulate the patient respiratory motion during the free‐breathing treatment. The results showed that the respiratory cycle period and radiation beam‐on timing presented limited impact on the target dose coverage and slightly increased the target dose heterogeneity. This motion impact tended to increase the variation of target dose coverage and heterogeneity between treatment fractions with different radiation beam‐on timing. The target dose coverage and heterogeneity were more susceptible to the radiation beam‐on timing for patients with long respiratory cycle (longer than ) and large breast motion amplitudes (larger than ). The same results could be found for respiratory cycle up to and respiratory motion amplitude up to . The heart dose distribution did not change significantly regardless of respiratory cycle and radiation beam‐on timing.
Model‐based cartilage thickness measurement in the submillimeter range
Authors: Streekstra G. J. , Strackee S. D. , Maas M. , ter Wee R. , Venema H. W.
Published: September 2007

Current methods of image‐based thickness measurement in thin sheet structures utilize second derivative zero crossings to locate the layer boundaries. It is generally acknowledged that the nonzero width of the point spread function (PSF) limits the accuracy of this measurement procedure. We propose a model‐based method that strongly reduces PSF‐induced bias by incorporating the PSF into the thickness estimation method. We estimated the bias in thickness measurements in simulated thin sheet images as obtained from second derivative zero crossings. To gain insight into the range of sheet thickness where our method is expected to yield improved results, sheet thickness was varied between 0.15 and with an assumed PSF as present in the high‐resolution modes of current computed tomography (CT) scanners [full width at half maximum (FWHM) ]. Our model‐based method was evaluated in practice by measuring layer thickness from CT images of a phantom mimicking two parallel cartilage layers in an arthrography procedure. CT arthrography images of cadaver wrists were also evaluated, and thickness estimates were compared to those obtained from high‐resolution anatomical sections that served as a reference. The thickness estimates from the simulated images reveal that the method based on second derivative zero crossings shows considerable bias for layers in the submillimeter range. This bias is negligible for sheet thickness larger than , where the size of the sheet is more than twice the FWHM of the PSF but can be as large as for a sheet. The results of the phantom experiments show that the bias is effectively reduced by our method. The deviations from the true thickness, due to random fluctuations induced by quantum noise in the CT images, are of the order of 3% for a standard wrist imaging protocol. In the wrist the submillimeter thickness estimates from the CT arthrography images correspond within 10% to those estimated from the anatomical sections. We present a method that yields virtually unbiased thickness estimates of cartilage layers in the submillimeter range. The good agreement of thickness estimates from CT images with estimates from anatomical sections is promising for clinical application of the method in cartilage integrity staging of the wrist and the ankle.
Systematic errors in respiratory gating due to intrafraction deformations of the liver
Authors: von Siebenthal Martin , Székely Gábor , Lomax Antony J. , Cattin Philippe C.
Published: September 2007

This article shows the limitations of respiratory gating due to intrafraction deformations of the right liver lobe. The variability of organ shape and motion over tens of minutes was taken into account for this evaluation, which closes the gap between short‐term analysis of a few regular cycles, as it is possible with 4DCT, and long‐term analysis of interfraction motion. Time resolved MR volumes (4D MR sequences) were reconstructed for 12 volunteers and subsequent non‐rigid registration provided estimates of the 3D trajectories of points within the liver over time. The full motion during free breathing and its distribution over the liver were quantified and respiratory gating was simulated to determine the gating accuracy for different gating signals, duty cycles, and different intervals between patient setup and treatment. Gating effectively compensated for the respiratory motion within short sequences , but deformations, mainly in the anterior inferior part (Couinaud segments IVb and V), led to systematic deviations from the setup position of more than in 7 of 12 subjects after . We conclude that measurements over a few breathing cycles should not be used as a proof of accurate reproducibility of motion, not even within the same fraction, if it is longer than a few minutes. Although the diaphragm shows the largest magnitude of motion, it should not be used to assess the gating accuracy over the entire liver because the reproducibility is typically much more limited in inferior parts. Simple gating signals, such as the trajectory of skin motion, can detect the exhalation phase, but do not allow for an absolute localization of the complete liver over longer periods because the drift of these signals does not necessarily correlate with the internal drift.
CT image registration in sinogram space
Authors: Mao Weihua , Li Tianfang , Wink Nicole , Xing Lei
Published: September 2007

Object displacement in a CT scan is generally reflected in CT projection data or sinogram. In this work, the direct relationship between object motion and the change of CT projection data (sinogram) is investigated and this knowledge is applied to create a novel algorithm for sinogram registration. Calculated and experimental results demonstrate that the registration technique works well for registering rigid 2D or 3D motion in parallel and fan beam samplings. Problem and solution for 3D sinogram‐based registration of metallic fiducials are also addressed. Since the motion is registered before image reconstruction, the presented algorithm is particularly useful when registering images with metal or truncation artifacts. In addition, this algorithm is valuable for dealing with situations where only limited projection data are available, making it appealing for various applications in image guided radiation therapy.
Empirical dual energy calibration (EDEC) for cone‐beam computed tomography
Authors: Stenner Philip , Berkus Timo , Kachelriess Marc
Published: September 2007

Material‐selective imaging using dual energy CT (DECT) relies heavily on well‐calibrated material decomposition functions. These require the precise knowledge of the detected x‐ray spectra, and even if they are exactly known the reliability of DECT will suffer from scattered radiation. We propose an empirical method to determine the proper decomposition function. In contrast to other decomposition algorithms our empirical dual energy calibration (EDEC) technique requires neither knowledge of the spectra nor of the attenuation coefficients. The desired material‐selective raw data and are obtained as functions of the measured attenuation data and (one DECT raw data sets) by passing them through a polynomial function. The polynomial's coefficients are determined using a general least squares fit based on thresholded images of a calibration phantom. The calibration phantom's dimension should be of the same order of magnitude as the test object, but other than that no assumptions on its exact size or positioning are made. Once the decomposition coefficients are determined DECT raw data can be decomposed by simply passing them through the polynomial. To demonstrate EDEC simulations of an oval CTDI phantom, a lung phantom, a thorax phantom and a mouse phantom were carried out. The method was further verified by measuring a physical mouse phantom, a half‐and‐half‐cylinder phantom and a Yin‐Yang phantom with a dedicated in vivo dual source micro‐CT scanner. The raw data were decomposed into their components, reconstructed, and the pixel values obtained were compared to the theoretical values. The determination of the calibration coefficients with EDEC is very robust and depends only slightly on the type of calibration phantom used. The images of the test phantoms (simulations and measurements) show a nearly perfect agreement with the theoretical values and density values. Since EDEC is an empirical technique it inherently compensates for scatter components. The empirical dual energy calibration technique is a pragmatic, simple, and reliable calibration approach that produces highly quantitative DECT images.
Toward Direct Measurement of Atmospheric Nucleation
Authors: Kulmala Markku , Riipinen Ilona , Sipilä Mikko , Manninen Hanna E. , Petäjä Tuukka , Junninen Heikki , Maso Miikka Dal , Mordas Genrik , Mirme Aadu , Vana Marko , Hirsikko Anne , Laakso Lauri , Harrison Roy M. , Hanson Ian , Leung Carl , Lehtinen Kari E. J. , Kerminen Veli-Matti
Published: August 2007

Atmospheric aerosol formation is known to occur almost all over the world, and the importance of these particles to climate and air quality has been recognized. Although almost all of the processes driving aerosol formation take place below a particle diameter of 3 nanometers, observations cover only larger particles. We introduce an instrumental setup to measure atmospheric concentrations of both neutral and charged nanometer-sized clusters. By applying the instruments in the field, we come to three important conclusions: (i) A pool of numerous neutral clusters in the sub–3 nanometer size range is continuously present; (ii) the processes initiating atmospheric aerosol formation start from particle sizes of ∼1.5 nanometers; and (iii) neutral nucleation dominates over the ion-induced mechanism, at least in boreal forest conditions.
Electrocatalytic Response and Determination of Noradrenaline in the Presence of L-Ascorbic and Uric Acids with Poly(Eriochrome Black T)-Modified Electrode
Authors: Lin Xinhua , Li Wei , Yao Hong , Sun Yuanyuan , Huang Liying , Zheng Yanjie
Published: August 2007

A poly(Eriochrome Black T) chemically modified glassy carbon electrode modified with Eriochrome Black T was prepared by cyclic voltammetry. The modified electrode showed an excellent electrocatalytic activity in oxidation of noradrenaline (NA) and could separate its electrochemical responses from those of L-ascorbic acid (AA) and uric acid (UA). Differences of the oxidation peak potentials for NA-AA and UA-NA were about 150 mV. The responses to NA, AA and UA of the modified electrode are relatively independent. Using differential pulse voltammetry, the peak currents of NA at modified glassy carbon electrode increased linearly with the concentration of NA from 0.5 to 100 μmol l-1. The detection limit was 0.2 μmol l-1. With the modified electrode, UA could be selectively determined in the presence of AA. The method showing a wide linear dynamic range and excellent sensitivity was successfully applied to the determination of NA in pharmaceutical injections and various samples.
A new 2-regression model for the Actical accelerometer
Authors: Crouter S E , Bassett D R
Published: August 2007

Objective:

The objective of this study was to develop a new 2-regression model relating Actical activity counts to METs.

Methods:

Forty-eight participants (mean (SD) age 35 (11.4) years) performed 10 min bouts of various activities ranging from sedentary behaviours to vigorous physical activities. Eighteen activities were split into three routines with each routine being performed by 20 individuals. Forty-five routines were randomly selected for the development of a new 2-regression model and 15 tests were used to cross-validate the new 2-regression model and compare it against existing equations. During each routine, the participant wore an Actical accelerometer on the hip and oxygen consumption was simultaneously measured by a portable metabolic system. The coefficient of variation (CV) of four consecutive 15 s epochs was calculated for each minute. For each activity, the average CV and the counts min−1were calculated for minutes 4–9. If the CV was ⩽13% a walk/run regression equation was used and if the CV was >13% a lifestyle/leisure time physical activity regression was used.

Results:

An exponential regression line (R2 = 0.912; standard error of the estimate (SEE) = 0.149) was used for activities with a CV⩽13%, and a cubic regression line (R2 = 0.884, SEE = 0.804) was used for activities with a CV>13%. In the cross-validation group the mean estimates, using the new 2-regression model with an inactivity threshold, were within 0.56 METs of measured METs for each of the activities performed (p⩾0.05), except cycling (p<0.05).

Conclusion:

For most activities examined the new 2-regression model predicted METs more accurately than currently available equations for the Actical accelerometer.