bluuebunny/crossref_metadata_2025 huggingface dataset:
Evolution of Pores and Tortuosity During Sintering
Authors: Hu Zhihao , Lu Kathy
Published: July 2014

Pores play an important role in sintering densification. In this study, 3D microstructure reconstruction has been used to quantitatively evaluate pore evolution during sintering. Pore shape, distribution, and connectivity are displayed in 3D based on actual microstructure data and show drastic differences from the conventional description of pores. Pore volume fraction and pore number density are extracted from the 3D microstructure reconstruction and compared. Pore size distribution frequency with sintering time is obtained. New tortuosity concept is provided to properly represent pore shape changes during sintering.
MicroRNA‐302b‐inhibited E2F3 transcription factor is related to all trans retinoic acid‐induced glioma cell apoptosis
Authors: Chen Peng‐Hsu , Shih Chwen‐Ming , Chang Wei‐Chiao , Cheng Chia‐Hsiung , Lin Cheng‐Wei , Ho Kuo‐hao , Su Po‐Chia , Chen Ku‐Chung
Published: July 2014

All‐trans retinoic acid (ATRA), a derivative of retinoid, is involved in the onset of differentiation and apoptosis in a wide variety of normal and cancer cells. MicroRNAs (miRNAs) are small non‐coding RNAs that control gene expression. Several miRNAs were identified to participate in ATRA‐mediated cell differentiation. However, no studies have demonstrated whether miRNA can enhance ATRA cytotoxicity, thereby resulting in cell apoptosis. This study investigated the effects of ATRA‐mediated miRNA expression in activating apoptotic pathways in glioblastoma. First, we found that high‐dose ATRA treatment significantly reduced cell viability, caspase‐dependent apoptosis, endoplasmic reticular (ER) stress activation, and intracellular reactive oxygen species accumulation. From microarray data, miR‐302b was analyzed as a putative downstream regulator upon ATRA treatment. Furthermore, we found that ATRA up‐regulated miR‐302b expression in a dose‐ and time‐dependent manner through retinoic acid receptor α‐mediated pathway. Overexpression and knockdown of miR‐302b significantly influenced ATRA‐mediated cytotoxicity. E2F3, an important transcriptional regulator of glioma proliferation, was validated to be a direct target gene of miR‐302b. The miR‐302b‐reduced E2F3 levels were also identified to be associated with ATRA‐mediated glioma cell death. These results emphasize that an ATRA‐mediated miR‐302b network may provide novel therapeutic strategies for glioblastoma therapy.

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We propose that high‐dose all‐trans retinoic acid (ATRA) treatment, a derivative of retinoid, significantly induces glioblastoma cell apoptosis via caspase‐dependent apoptosis, endoplasmic reticular (ER) stress, and intracellular reactive oxygen species (ROS) accumulation. The miR‐302b overexpression enhanced by ATRA‐mediated retinoic acid receptor (RAR)α pathway was also identified. The E2F3 repression, a novel target gene of miR‐302b, was involved in ATRA‐induced glioblastoma cell cytotoxicity.
Happiness in Motion: Emotions, Well‐Being, and Active School Travel
Authors: Ramanathan Subha , O'Brien Catherine , Faulkner Guy , Stone Michelle
Published: July 2014

BACKGROUND

A pan‐Canadian School Travel Planning intervention promoted active school travel (AST). A novel component was exploring emotion, well‐being, and travel mode framed by the concept of “sustainable happiness.” Relationships between travel mode and emotions, parent perceptions of their child's travel mode on well‐being, and factors related to parent perceptions were examined.

METHODS

Questionnaires were administered to families (N = 5423) from 76 elementary schools. Explanatory variables were demographics (age and sex), school travel measures (mode, distance, accompaniment by an adult, safety, and barriers), and emotions (parent and child). Outcomes examined parent perceived benefits of travel mode on dimensions of well‐being (physical, emotional, community, and environmental). Descriptive statistics, chi‐square tests and hierarchical regression were used.

RESULTS

Parents and children who used AST reported more positive emotions versus passive travelers. Parents of active travelers reported stronger connections to dimensions of well‐being. AST had the strongest association with parents' perceptions of their child's well‐being, and positive emotions (parent and child) were also significantly related to well‐being on the trip to school.

CONCLUSIONS

As an additional potential benefit of AST, interventions should raise awareness of the positive emotional experiences for children and their parents. Future research should experimentally examine if AST causes these emotional benefits.
Area Disparity in Children's Perceptions of Access to Tobacco and Cigarette Purchasing Experiences in Taiwan
Authors: Lee Heng , Hsu Chih‐Cheng , Chen Fu‐Li , Yen Yea‐Yin , Lin Pi‐Li , Chiu Yu‐Wen , Lee Chien‐Hung , Peng Wu‐Der , Chen Ted , Lu Di‐Lin , Huang Hsiao‐Ling
Published: July 2014

BACKGROUND

Adolescents who perceive easy access to tobacco are more likely to acquire cigarettes and experience smoking. This study assesses area disparities in perceptions of access to tobacco and cigarette purchasing experiences among schoolchildren.

METHODS

Data on children's tobacco‐related variables were obtained from the Control of School‐Aged Children Smoking Study Survey in Taiwan. A stratified random sample of 65 primary schools was included. Polytomous logistic regression analyzed factors associated with tobacco accessibility and purchasing experiences.

RESULTS

More than half of the children reported that tobacco retailers often or always sold cigarettes to them. Rural and mountainous children were more likely to have access to cigarettes (adjusted odds ratio [AOR] = 2.01 and 3.01, respectively) and have cigarette purchasing experiences (AOR = 3.06 and 13.76, respectively). Cigarette purchasing from retailers (AOR = 1.84) was significantly associated with children's perceptions of access to tobacco. The factors associated with cigarette purchasing experiences were families smoking (AOR = 8.90), peers smoking (AOR = 2.22), frequent exposure to entertainer smoking on TV and in films (AOR = 2.15), and perceived access to tobacco (AOR = 1.51).

CONCLUSIONS

The health department should strictly enforce laws regarding retailers selling tobacco to underage, particularly in remote areas. Schools can reinforce tobacco‐use prevention messages.
Usual Source of Cigarettes and Alcohol Among US High School Students
Authors: Everett Jones Sherry , Caraballo Ralph S.
Published: July 2014

BACKGROUND

Cigarette and alcohol use are common among youth. We examined sources of cigarettes and alcohol among youth who were current cigarette and alcohol users.

METHODS

We analyzed nationally representative data from the 2009 and 2011 national Youth Risk Behavior Surveys—biennial, school‐based surveys of high school students in the United States. Students completed anonymous, self‐administered questionnaires. Overall response rates were 71% for both years.

RESULTS

Among the 17.3% of current cigarette users <18 years, 27.3% usually gave someone else money to buy their cigarettes and 27.7% usually borrowed (bummed) them. Fewer (14.1%) usually bought their own cigarettes in a store. Among the 40.3% of current alcohol users, 24.3% usually gave someone else money to buy it and 41.2% usually had someone give it to them. A few (4.5%) usually bought their own alcohol in a store. Age and intensity of use were positively associated with students buying their own cigarettes or alcohol, but negatively associated with students borrowing or having someone else give it to them.

CONCLUSIONS

Because social and commercial sources of cigarettes and alcohol are common, multiple strategies are needed to reduce the ability for youth to obtain them and reduce their desire for them.
The Impact of a Physical Activity Intervention Program on Academic Achievement in a Swedish Elementary School Setting
Authors: Käll Lina B. , Nilsson Michael , Lindén Thomas
Published: July 2014

BACKGROUND

Despite the emerging body of research on the potential of physical activity to improve learning and academic achievement, conclusive evidence regarding the effects of physical activity on academic achievement is lacking. The objective of this study was to determine the impact of a physical activity intervention program on academic performance.

METHODS

A controlled cross‐sectional design was used to investigate the hypothesis that the intervention program would increase the proportion of students in grade 5 who achieved the national learning goals in Swedish, mathematics, and English compared with 3 reference schools. Academic results from the years prior to and during the intervention program were analyzed. Logistic regression analyses assessed the odds of achieving the national learning goals when the intervention program was integrated into the elementary curricula.

RESULTS

Higher proportions of students in the intervention school achieved the national goals in all 3 subjects compared with the reference schools after initiation of the intervention program. The odds for achieving the national learning goals in the intervention school increased 2‐fold (p < .05), whereas these odds either did not change or decreased in the reference schools.

CONCLUSION

Promoting physical activity in school by means of a curriculum‐based intervention program may improve children's educational outcome.
Phytophthora Crown and Root Rot of Apricot Caused by Phytophthora palmivora in Turkey
Authors: Türkölmez Şahimerdan , Çiftçi Osman , Canıhoş Ercan , Serçe Çigdem U. , Derviş Sibel
Published: July 2014

Forty‐nine Phytophthora isolates were obtained from roots and crown of apricot trees with symptoms of decline grown in commercial orchards in Malatya, Elazığ and Diyarbakır provinces, Turkey, in 2011 and 2013. All of the recovered isolates were identified as Phytophthora palmivora on the basis of morphological characteristics. Blast analysis of ITS region sequences of rDNA of 5 isolates revealed 100% identity with a reference isolates of P. palmivora from GenBank. Isolates of P. palmivora were pathogenic on 12‐month‐old wild apricot rootstock ‘Zerdali’ plants that were wound inoculated on the roots and on the crown. This study demonstrated that P. palmivora is the cause of the crown and root rot found on apricot in Turkey. To our knowledge, this is the first report of P. palmivora on this host plant.
Determinants of Sexual Impairment in Multiple Sclerosis in Male and Female Patients with Lower Urinary Tract Dysfunction: Results from an Italian Cross-Sectional Study
Authors: Fragalà Eugenia , Privitera Salvatore , Giardina Raimondo , Di Rosa Alessandro , Russo Giorgio Ivan , Favilla Vincenzo , Caramma Andrea , Patti Francesco , Cimino Sebastiano , Morgia Giuseppe
Published: July 2014

Introduction

Sexual dysfunction (SD) is prevalent in multiple sclerosis (MS) patients and affects quality of life. Furthermore, lower urinary tract dysfunction (LUTD) is common in MS patients.

Aims

This study aims to evaluate the relationship between SD, neurological disability, depression, anxiety, and urodynamic alterations in patients with MS and LUTD.

Methods

From January 2011 to September 2013, 135 consecutive patients with MS in remission phase and LUTD underwent first urodynamic examination, according to the International Continence Society criteria. Depression and anxiety were evaluated with the Hamilton Depression Scale (HAM-D) and the Hamilton Anxiety Scale (HAM-A), neurological impairment was assessed using the Expanded Disability Status Scale (EDSS), and SD was investigated with the Female Sexual Function Index (FSFI) or the International Index of Erectile Function (IIEF-15).

Main Outcome Measures

Multivariate logistic regression analyses were carried out to identify variables for predicting female sexual dysfunction (FSD) (FSFI < 26.55), male SD (IIEF-15 < 60), or moderate-severe erectile dysfunction (IIEF-EF ≤ 16), after adjusting for confounding factors.

Results

Total IIEF-15 and all subdomains (all P < 0.01), total FSFI, FSFI-arousal, FSFI-lubrication, and FSFI-orgasm (all P < 0.05) were lower in subjects with EDSS ≥ 4.5. We found inverse relationship between IIEF-15 and relative subdomains with EDSS (all P < 0.01) and between FSFI and relative subdomains with EDSS (all P < 0.01), HAM-D (all P < 0.01), and HAM-A (all P < 0.01). Continuous EDSS (odds ratio [OR] = 1.54; P = 0.03) and categorical EDSS (≥4.5) (OR = 6.0; P = 0.03), HAM-D (OR = 4.74; P = 0.03), and HAM-A (OR = 4.10; P = 0.02) were significantly associated with FSD (FSFI < 26.55). Detrusor overactivity (DO) was an independent predictor of moderate-severe ED (IIEF-EF ≤ 16) (OR = 2.03; P < 0.01), and of FSD (OR = 9.73; P = 0.04).

Conclusions

Neurological disability, depression and DO are significantly predictive of SD in MS patients, irrespective of gender. An EDSS ≥ 4.5 may significantly predict the presence of SD.
Invasive polychaete Boccardia proboscidea Hartman, 1940 (Polychaeta: Spionidae) in sewage‐impacted areas of the SW Atlantic coasts: morphological and reproductive patterns
Authors: Jaubet María L. , Garaffo Griselda V. , Vallarino Eduardo A. , Elías Rodolfo
Published: July 2014

Boccardia proboscidea is an alien polychaete species that has been introduced to the Southwestern Atlantic Ocean. This polychaete species has invaded intertidal benthic rocky shores, and builds reefs formed by thousands of individuals per square meter with densities up to 1,500,000 ind.·m−2 in organically impacted sites. This phenomenon was first recorded in Argentina in 2008. This is the first comprehensive study on the morphology, habitat and reproductive biology of B. proboscidea associated with the sewage‐induced abrasion platforms on the Argentinean coasts. Adult morphology of B. proboscidea from Mar del Plata is described and a comparison with material from other locations is made. Results showed that B. proboscidea from Mar del Plata, Argentina share the same diagnostic features as those of the individuals from the original description (California). Moreover, the results also indicated that the reproduction of this species involves a poecilogonous development (production of more than one type of offspring with both kinds of larvae) and implicates adelphophagy (nurse egg ingestion). Patterns of larval development varied both within a single brood and among broods of different females. Continuous reproduction of B. proboscidea coupled with a continuous supply of organic matter could explain the possible mechanism that led to the development of reefs.
Urban population genetics of slum‐dwelling rats (Rattus norvegicus) in Salvador, Brazil
Authors: Kajdacsi Brittney , Costa Federico , Hyseni Chaz , Porter Fleur , Brown Julia , Rodrigues Gorete , Farias Helena , Reis Mitermayer G. , Childs James E. , Ko Albert I. , Caccone Adalgisa
Published: July 2014

Throughout the developing world, urban centres with sprawling slum settlements are rapidly expanding and invading previously forested ecosystems. Slum communities are characterized by untended refuse, open sewers and overgrown vegetation, which promote rodent infestation. Norway rats (Rattus norvegicus) are reservoirs for epidemic transmission of many zoonotic pathogens of public health importance. Understanding the population ecology of R. norvegicus is essential to formulate effective rodent control strategies, as this knowledge aids estimation of the temporal stability and spatial connectivity of populations. We screened for genetic variation, characterized the population genetic structure and evaluated the extent and patterns of gene flow in the urban landscape using 17 microsatellite loci in 146 rats from nine sites in the city of Salvador, Brazil. These sites were divided between three neighbourhoods within the city spaced an average of 2.7 km apart. Surprisingly, we detected very little relatedness among animals trapped at the same site and found high levels of genetic diversity, as well as structuring across small geographical distances. Most FST comparisons among sites were statistically significant, including sites <400 m apart. Bayesian analyses grouped the samples in three genetic clusters, each associated with distinct sampling sites from different neighbourhoods or valleys within neighbourhoods. These data indicate the existence of complex genetic structure in R. norvegicus in Salvador, linked to the heterogeneous urban landscape. Future rodent control measures need to take into account the spatial and temporal linkage of rat populations in Salvador, as revealed by genetic data, to develop informed eradication strategies.
Distinct characteristics of OxyR2, a new OxyR‐type regulator, ensuring expression of Peroxiredoxin 2 detoxifying low levels of hydrogen peroxide in Vibrio vulnificus
Authors: Kim Suyeon , Bang Ye‐Ji , Kim Dukyun , Lim Jong Gyu , Oh Man Hwan , Choi Sang Ho
Published: July 2014

Two peroxiredoxins, Prx1 and Prx2, were previously identified in Vibrio vulnificus. Besides OxyR1, a homologue of Escherichia coli OxyR (EcOxyR), OxyR2 that shares low homology with EcOxyR was first identified in V. vulnificus. OxyR2 activated prx2 during aerobic growth, while OxyR1 activated prx1 only when exposed to exogenous H2O2. OxyR2 was oxidized to form a reversible C206 to C215 disulphide bond by sensing low levels of H2O2, which were insufficient to oxidize OxyR1, and only the oxidized OxyR2 activated prx2. OxyR25CA, in which all cysteine residues except for C206 and C215 were replaced with alanines, and its mutants, OxyR25CA‐C206S and OxyR25CA‐C215S, were constructed. OxyR25CA and OxyR25CA‐C215S directly bound to a specific binding sequence centred at −56.5 from the prx2 transcription start site, albeit with different binding affinities. The binding sequence consisted of four ATCGnt elements spaced by a helical turn and aligned in the twofold dyad symmetry, suggesting that OxyR2 binds DNA as a tetramer. OxyR25CA‐C206S also directly bound to DNA comprising more extended sequences, indicating that oxidized and reduced OxyR2 adopt different conformational states, leading to altered DNA contacts. The oxyR2 mutation reduced cytotoxicity and growth during infection, indicating that OxyR2 is essential for the pathogenesis of V. vulnificus.
Will smaller plates lead to smaller waists? A systematic review and meta‐analysis of the effect that experimental manipulation of dishware size has on energy consumption
Authors: Robinson E. , Nolan S. , Tudur‐Smith C. , Boyland E. J. , Harrold J. A. , Hardman C. A. , Halford J. C. G.
Published: July 2014

It has been suggested that providing consumers with smaller dishware may prove an effective way of helping people eat less and preventing weight gain, but experimental evidence supporting this has been mixed. The objective of the present work was to examine the current evidence base for whether experimentally manipulated differences in dishware size influence food consumption. We systematically reviewed studies that experimentally manipulated the dishware size participants served themselves at a meal with and measured subsequent food intake. We used inverse variance meta‐analysis, calculating the standardized mean difference (SMD) in food intake between smaller and larger dishware size conditions. Nine experiments from eight publications were eligible for inclusion. The majority of experiments found no significance difference in food intake when participants ate from smaller vs. larger dishware. With all available data included, analysis indicated a marginal effect of dishware size on food intake, with larger dishware size associated with greater intake. However, this effect was small and there was a large amount of heterogeneity across studies (SMD: −0.18, 95% confidence interval: −0.35, 0.00, I2 = 77%). Evidence to date does not show that dishware size has a consistent effect on food intake, so recommendations surrounding the use of smaller plates/dishware to improve public health may be premature.
Romiplostim treatment allows for platelet transfusion‐free liver transplantation in pediatric thrombocytopenic patient with primary sclerosing cholangitis
Authors: Minowa Kei , Arai Katsuhiro , Kasahara Mureo , Sakamoto Seisuke , Shimizu Hirotaka , Nakano Natsuko , Ito Reiko , Obayashi Naho , Nakazawa Atsuko , Ishiguro Akira
Published: July 2014

Thrombocytopenia is a major risk factor for cirrhotic liver disease. Patients with thrombocytopenia may have esophageal or gastric varices secondary to portal hypertension, leading to variceal bleeding which exposes the liver to further damage. Here, we present a female pediatric patient with PSC and CD, whose progressive thrombocytopenia was successfully controlled by romiplostim, a TPO receptor agonist. The patient developed bloody diarrhea at four yr of age, and was subsequently diagnosed with PSC and CD when seven yr old. While CD was well‐controlled by immunomodulators, the patient's thrombocytopenia gradually progressed resulting in petechiae (platelet count of 11 × 109/L) when she was 10 yr and four months old. She responded poorly to immunoglobulin and corticosteroids. Weekly subcutaneous injection of romiplostim was therefore initiated, and platelet counts were maintained over at 50 × 109/L. She was able to undergo successful LDLT without platelet transfusion seven months after the initiation of romiplostim. Romiplostim was not required after LDLT with improved platelet counts. This case report suggests that romiplostim may be effective in the treatment of thrombocytopenic children with liver cirrhosis and portal hypertension, and in eliminating the need for platelet transfusion during the peri‐transplant period.
Capital Inflows, Exchange Rate Flexibility and Credit Booms
Authors: Magud Nicolas E. , Reinhart Carmen M. , Vesperoni Esteban R.
Published: July 2014

Historically, capital flow bonanzas have often fueled sharp credit expansions in advanced and emerging market economies alike. Focusing primarily on emerging markets, this paper analyzes the impact of exchange rate flexibility on credit markets during periods of large capital inflows. It is shown that bank credit is larger and its composition tilts to foreign currency in economies with less flexible exchange rate regimes, and that these results are not explained entirely by the fact that the latter attract more capital inflows than economies with more flexible regimes. The findings thus suggest countries with less flexible exchange rate regimes may stand to benefit the most from regulatory policies that reduce banks' incentives to tap external markets and to lend/borrow in foreign currency; these policies include marginal reserve requirements on foreign lending, currency‐dependent liquidity requirements and higher capital requirement and/or dynamic provisioning on foreign exchange loans.
The Structure ofEurope: International Input–Output Analysis with Trade in Intermediate Inputs and Capital Flows
Authors: Benz Sebastian , Larch Mario , Zimmer Markus
Published: July 2014

In this paper we theoretically derive an internationalRybczynski matrix. Its elements indicate the aggregate output change in a country when endowment with one or more factors in the same or another country is increased. This allows us to characterize the production structure in 11 countries of theEuropeanUnion. Starting from a baseline case with free trade in final goods only, we analyze two types of interaction between countries: international trade of intermediate inputs and internationally mobile capital.
Do Capital Controls Enhance Monetary Independence?
Authors: You Yu , Kim Yoonbai , Ren Xiaomei
Published: July 2014

International monetary policy trilemma—the tradeoff among exchange rate stability, monetary independence, and unrestricted capital mobility—is an important constraint for policy makers in an open economy. This paper investigates an aspect of the hypothesis that has received relatively less attention: whether a decrease in capital mobility through imposition of capital controls, while holding the degree of exchange rate stability constant, will enhance monetary independence. Using a panel dataset covering 88 countries for the 1995–2010 period and the generalized method of moments (GMM) estimation, we find that: (1) capital controls help improve a country's monetary independence; (2) the effectiveness of capital controls depends on the types of assets and the direction of flows that are imposed; and (3) the choice of exchange rate regime has an important impact on the effectiveness of capital controls on monetary independence.
Strategic Investment Subsidies under Asymmetric Oligopoly
Authors: Jinji Naoto , Toshimitsu Tsuyoshi
Published: July 2014

This paper examines strategic investment subsidies in an international oligopoly. A general oligopoly model is constructed in which firms compete in two stages and governments commit to investment subsidies prior to firms' actions. The paper considers asymmetry among firms that arises from the nature of goods they produce rather than their cost structures. When firms produce asymmetrically differentiated goods, it is found that a change in the number of foreign competitors may alter the sign of the optimal unilateral investment subsidy. An example of policy reversal is provided in the case of strategic research and development subsidies for a quality‐differentiated industry.
The Volatility of Foreign Portfolio Investment and the Access to Finance of Small Listed Firms
Authors: Knill April , Lee Bong Soo
Published: July 2014

This paper examines the impact of foreign portfolio investment (FPI) volatility on the access to capital of small listed firms. The volatility of FPI is significantly associated with decreased access to finance for small listed firms only in years when nations are considered less “creditworthy.” Even in these times, however, the benefits of FPI are not completely depleted. These results underscore the significance of both a good financial system that minimizes capital flow volatility and national creditworthiness in inspiring confidence in foreign investors.
Do the Effects of Corruption upon Growth Differ Between Democracies and Autocracies?
Authors: Assiotis Andreas , Sylwester Kevin
Published: July 2014

Many studies examining whether corruption lowers economic growth do not consider if the effects of corruption differ across countries. Whether corruption produces the same effects everywhere or whether its effects are conditional on some country characteristics are important questions. We investigate the association between corruption and growth, where the marginal impact of corruption is allowed to differ across democratic and nondemocratic regimes. Using cross‐country, annual data from 1984 to 2007, we regress growth on corruption, democracy and their interaction. We find that decreases in corruption raise growth but more so in authoritarian regimes. Possible reasons are that in autocracies corruption causes more uncertainty, is of a more pernicious nature, or is less substitutable with other forms of rent seeking.
Susceptibility to imazamox in Italian weedy rice populations and Clearfield® rice varieties
Authors: Andres A , Fogliatto S , Ferrero A , Vidotto F
Published: July 2014

The introduction of imidazolinone‐tolerant rice varieties has made selective Oryza sativa (weedy rice) control possible. We hypothesised that Italian weedy rice populations have variable degrees of susceptibility to imazamox prior to imidazolinone‐tolerant variety introduction. To this end, 149 Italian weedy rice populations collected from fields never before cultivated with imidazolinone‐tolerant varieties were tested in a glasshouse‐based, whole‐plant response screening study. Imazamox was applied to all populations post‐emergence at a rate of 70 g a.i. ha−1, resulting in 70–90% shoot biomass reduction in the majority of cases. The results prompted a second study of the seedling dose response of four weedy rice populations from the initial study group. Three imidazolinone‐tolerant and one conventional rice variety were also included. The seedling roots were cut six days after germination and exposed to different concentrations of imazamox. The root regrowth associated with each concentration‐exposure was then measured. Imazamox concentrations to inhibit weedy rice root growth by 50% varied by about two orders of magnitude, or between 0.0018 and 0.12 mm. Even with this result, imidazolinone‐tolerant varieties were at least 31.8 times less susceptible than weedy rice populations, suggesting that Italian weedy rice populations were not tolerant to imazamox before introduction of these varieties.
Crossing Over: Raising the ghosts of Tasman-Pacific art exchange: ANZART-in-HOBART, 1983
Authors: Zeplin Pamela
Published: July 2014

Crossing Over: Raising the ghosts of Tasman-Pacific art exchange: ANZART-in-HOBART, 1983
Interview with Kate Roberts, Manager/Curator Art Development Govett-Brewster Art Gallery, New Plymouth
Authors: Roberts Kate
Published: July 2014

Interview with Kate Roberts, Manager/Curator Art DevelopmentGovett-Brewster Art Gallery, New Plymouth
Contemporary Identity, Culture and the Art of Redress: Tokyo Street Style and Shigeyuki Kihara in Aotearoa New Zealand
Authors: Message Kylie
Published: July 2014

Contemporary Identity, Culture and the Art of Redress: Tokyo Street Style and Shigeyuki Kihara in Aotearoa New Zealand
Parallel Quotidian Flows: Maori Television On Air
Authors: Smith Jo T.
Published: July 2014

Parallel Quotidian Flows: Maori Television On Air
Dual-superlattice calibrations for group-III species in III-V semiconductor epitaxial structure growth
Authors: Leavitt Richard P. , He Lei , Richardson Christopher J. K.
Published: July 2014

High-resolution x-ray diffraction analysis of superlattice structures is often used to calibrate epitaxial growth systems. In most cases, systematic errors introduce biases that overwhelm the random measurement error, thus requiring a series of calibrations to be completed in order to target a narrow range of materials. Structures consisting of two superlattices grown with a single pair of group-III sources offer significant improvements in calibrating group-III growth rates over conventional single-superlattice structures. It is shown that these dual superlattices avoid pitfalls associated with uncertainty and variability in the lattice constants and elastic constants of the constituent materials as well as those of the substrate. Analyses of the high-resolution x-ray diffraction spectra for several different binary/binary, ternary/binary, and quaternary/binary superlattices provide accurate determination of group-III beam fluxes, leading to the capability of reproducing growth rates with accuracy of within 1%.
A complete software application for automatic registration of x‐ray mammography and magnetic resonance images
Authors: Solves‐Llorens J. A. , Rupérez M. J. , Monserrat C. , Feliu E. , García M. , Lloret M.
Published: July 2014

Purpose:

This work presents a complete and automatic software application to aid radiologists in breast cancer diagnosis. The application is a fully automated method that performs a complete registration of magnetic resonance (MR) images and x‐ray (XR) images in both directions (from MR to XR and from XR to MR) and for both x‐ray mammograms, craniocaudal (CC), and mediolateral oblique (MLO). This new approximation allows radiologists to mark points in the MR images and, without any manual intervention, it provides their corresponding points in both types of XR mammograms and vice versa.

Methods:

The application automatically segments magnetic resonance images and x‐ray images using the C‐Means method and the Otsu method, respectively. It compresses the magnetic resonance images in both directions, CC and MLO, using a biomechanical model of the breast that distinguishes the specific biomechanical behavior of each one of its three tissues (skin, fat, and glandular tissue) separately. It makes a projection of both compressions and registers them with the original XR images using affine transformations and nonrigid registration methods.

Results:

The application has been validated by two expert radiologists. This was carried out through a quantitative validation on 14 data sets in which the Euclidean distance between points marked by the radiologists and the corresponding points obtained by the application were measured. The results showed a mean error of 4.2 ± 1.9 mm for the MRI to CC registration, 4.8 ± 1.3 mm for the MRI to MLO registration, and 4.1 ± 1.3 mm for the CC and MLO to MRI registration.

Conclusions:

A complete software application that automatically registers XR and MR images of the breast has been implemented. The application permits radiologists to estimate the position of a lesion that is suspected of being a tumor in an imaging modality based on its position in another different modality with a clinically acceptable error. The results show that the application can accelerate the mammographic screening process for high risk populations or for dense breasts.
Evaluating the utility of intraprocedural 3D TRUS image information in guiding registration for displacement compensation during prostate biopsy
Authors: De Silva Tharindu , Cool Derek W. , Romagnoli Cesare , Fenster Aaron , Ward Aaron D.
Published: July 2014

Purpose:

In targeted 3D transrectal ultrasound (TRUS)‐guided biopsy, patient and prostate movement during the procedure can cause target misalignments that hinder accurate sampling of preplanned suspicious tissue locations. Multiple solutions have been proposed for displacement compensation via registration of intraprocedural TRUS images to a baseline 3D TRUS image acquired at the beginning of the biopsy procedure. While 2D TRUS images are widely used for intraprocedural guidance, some solutions utilize richer intraprocedural images such as bi‐ or multiplanar TRUS or 3D TRUS, acquired by specialized probes. In this work, the impact of such richer intraprocedural imaging on displacement compensation accuracy was measured to evaluate the tradeoff between cost and complexity of intraprocedural imaging versus improved displacement compensation.

Methods:

Baseline and intraprocedural 3D TRUS images were acquired from 29 patients at standard sextant‐template biopsy locations. Planes extracted from 3D TRUS images acquired at sextant positions were used to simulate 2D and 3D intraprocedural information available in different potential clinically relevant scenarios for co‐registration with the baseline 3D TRUS image. In practice, intraprocedural 3D information can be acquired either via the use of specialized ultrasound probes (e.g., multiplanar or 3D probes) or via axial rotation of a tracked 2D TRUS probe. Registration accuracy was evaluated by calculating the target registration error (TRE) using manually identified homologous intrinsic fiducial markers (microcalcifications). The TRE was analyzed separately at the base, mid‐gland and apex regions of the prostate.

Results:

The results indicate that TRE improved gradually as the number of intraprocedural imaging planes used in registration was increased, implying that 3D TRUS information assisted the registration algorithm to robustly converge to more accurate solutions. The acquisition of a partial volume up to the angle of rotation supported more accurate displacement compensation than acquiring biplane configurations. Additional intraprocedural 3D TRUS image information was more beneficial to registration accuracy in the base and apex regions as compared with the mid‐gland region.

Conclusions:

While the majority of the registrations using 2D TRUS images provided a clinically desired level of accuracy, intraprocedural 3D imaging helped improve the overall registration accuracy and robustness, especially in the base and apex regions of the prostate. These results are helpful for devising image‐based registration methods for displacement compensation when designing 3D TRUS‐guided biopsy systems.
SU‐C‐17A‐05: Quantification of Intra‐Fraction Motion of Breast Tumors Using Cine‐MRI
Authors: van Heijst T , Philippens M , van den Bongard D , van Asselen B , Lagendijk J , Kleijnen J , den Hartogh M
Published: July 2014

Purpose:

Magnetic resonance imaging (MRI) enables direct characterization of intra‐fraction motion ofbreast tumors, due to high softtissue contrast and geometric accuracy. The purpose is to analyzethis motion in early‐stage breast‐cancer patients using pre‐operative supine cine‐MRI.

Methods:

MRI was performed in 12 female early‐stage breast‐cancer patients on a 1.5‐T Ingenia (Philips)wide‐bore scanner in supine radiotherapy (RT) position, prior to breast‐conserving surgery. Twotwodimensional (2D) T2‐weighted balanced fast‐field echo (cine‐MRI) sequences were added tothe RT protocol, oriented through the tumor. They were alternately acquired in the transverse andsagittal planes, every 0.3 s during 1 min. A radiation oncologist delineated gross target volumes(GTVs) on 3D contrast‐enhanced MRI. Clinical target volumes (CTV = GTV + 15 mm isotropic)were generated and transferred onto the fifth time‐slice of the time‐series, to which subsequents lices were registered using a non‐rigid Bspline algorithm; delineations were transformed accordingly. To evaluate intra‐fraction CTV motion, deformation fields between the transformed delineations were derived to acquire the distance ensuring 95% surface coverage during scanning(P95%), for all in‐plane directions: anteriorposterior (AP), left‐right (LR), and caudal‐cranial(CC). Information on LR was derived from transverse scans, CC from sagittal scans, AP fromboth sets.

Results:

Time‐series with registration errors – induced by motion artifacts – were excluded by visual inspection. For our analysis, 11 transverse, and 8 sagittal time‐series were taken into account. Themedian P95% calculated in AP (19 series), CC (8), and LR (11) was 1.8 mm (range: 0.9–4.8), 1.7mm (0.8–3.6), and 1.0 mm (0.6–3.5), respectively.

Conclusion:

Intra‐fraction motion analysis of breast tumors was achieved using cine‐MRI. These first results show that in supine RT position, motion amplitudes are limited. This information can be used for adaptive RT planning, and to develop preoperative partial‐breast RT strategies, such asablative RT for early‐stage breast‐cancer patients.
SU‐C‐18A‐03: Automatic Organ at Risk Delineation with Machine Learning Techniques
Authors: Bernard G , Verleysen M , Lee J
Published: July 2014

Purpose:

Manual delineation of organs at risk (OARs) on CT images consumes much time. Automatic segmentation methods like atlases partly address this issue. However, atlases depend on deformable registration quality. This work proposes an atlas‐like method that relies on machine learning techniques instead of registration.

Methods:

First, a watershed algorithm segments filtered CT images into superpixels (images patches with similar intensity pixels). Next, two kinds of superpixel features are computed: intrinsic ones (known at all times, like superpixel size, position, and mean intensity) and extrinsic ones (to be inferred from partial delineation results, like the distances to other organs). To build the atlas, a binary classifier is associated with each organ. Training optimizes the classifiers' parameters as well as their sequence, to make the most useful extrinsic features available as soon as possible. After training, the sequence of binary classifiers can process any new image, tagging all superpixels incrementally with an OAR label. The method was applied to 2D CT images of 49 breast‐cancer patients (axial slice passing through the 7th thoracic vertebra). The balanced classification rate (BCR) measures the method's accuracy, by giving the percentage of correctly classified pixels per label.

Results:

The proposed incremental method (BCR = 94%) is compared to two similar classification procedures, with either no extrinsic features (blind, BCR = 84%) or all of them known beforehand (cheating oracle, BCR = 98%). A preliminary comparison with a registration‐based atlas on synthetic data led to 97% (registration) and 98% (proposed).

Conclusion:

This abstract demonstrates the feasibility of atlas‐like OAR delineation based on machine learning techniques instead of deformable registration. The proposed method relies on incremental classification (partial classification allows additional highly informative features to be inferred). Involving no elastic deformation, delineation can be easily corrected if needed, just by changing the erroneous superpixel labels.

John Aldo Lee is a Research Associate with the Belgian fund of scientific research F.R.S‐FNRS.
SU‐C‐18A‐04: 3D Markerless Registration of Lung Based On Coherent Point Drift: Application in Image Guided Radiotherapy
Authors: Nasehi Tehrani J , Wang J , Guo X , Yang Y
Published: July 2014

Purpose:

This study evaluated a new probabilistic non‐rigid registration method called coherent point drift for real time 3D markerless registration of the lung motion during radiotherapy.

Method:

4DCT image datasets Dir‐lab (www.dir‐lab.com) have been used for creating 3D boundary element model of the lungs. For the first step, the 3D surface of the lungs in respiration phases T0 and T50 were segmented and divided into a finite number of linear triangular elements. Each triangle is a two dimensional object which has three vertices (each vertex has three degree of freedom). One of the main features of the lungs motion is velocity coherence so the vertices that creating the mesh of the lungs should also have features and degree of freedom of lung structure. This means that the vertices close to each other tend to move coherently. In the next step, we implemented a probabilistic non‐rigid registration method called coherent point drift to calculate nonlinear displacement of vertices between different expiratory phases.

Results:

The method has been applied to images of 10‐patients in Dir‐lab dataset. The normal distribution of vertices to the origin for each expiratory stage were calculated. The results shows that the maximum error of registration between different expiratory phases is less than 0.4 mm (0.38 SI, 0.33 mm AP, 0.29 mm RL direction). This method is a reliable method for calculating the vector of displacement, and the degrees of freedom (DOFs) of lung structure in radiotherapy.

Conclusions:

We evaluated a new 3D registration method for distribution set of vertices inside lungs mesh. In this technique, lungs motion considering velocity coherence are inserted as a penalty in regularization function. The results indicate that high registration accuracy is achievable with CPD. This method is helpful for calculating of displacement vector and analyzing possible physiological and anatomical changes during treatment.
SU‐C‐18C‐01: Surrogate Function Evaluation and Comparison for Atlas Selection in Multi‐Atlas‐Based Segmentation
Authors: Xie Q , Ruan D
Published: July 2014

Purpose:

To develop a systematic surrogate evaluation and comparison scheme to select a subset of training samples that best resemble the target in multi‐atlas‐based automatic segmentation, for the purpose of improved accuracy.

Methods:

In multi‐atlas‐based segmentation, it is desirable to fuse labels from a subset of training samples among the atlases that contribute positively to the final segmentation, for improved accuracy and efficiency. A surrogate metric is needed to prognosticate the contribution of a training image to the target segmentation. We formalize atlas subset selection as a ranking problem and develop a quality index to characterize the efficacy of a surrogate approach. A candidate surrogate is assessed in a supervised learning setting, where images with known segmentation are split into training atlases and testing targets, to enable assess to ground‐truth contribution level from a training atlas to the target, as measured by the Dice similarity coefficient (DSC). The quality index measures the discrepancy between (1) DSC in descending order as from an Oracle and (2) the reordered DSCs based on the surrogate metric. The quality index was applied in the context of automatic prostate and brain segmentations, to assess 6 surrogate candidates, namely, mean square error (MSE), normalized cross correlation (NCC), and mutual information (MI), either measured within a fixed region of interest (ROI), fROI, or adaptive ROI (aROI).

Results:

Surrogate metrics measured within aROI significantly outperform those within fROI (paired t‐test, p‐values consistently below 0.067), yet no statistically significant difference among MSE/NCC/MI (paired t‐test, 0.014≤p≤0.941).

Conclusion:

We have developed a quality index to quantitatively evaluate and compare surrogates' efficacy in atlas selection for automatic segmentation. When applied to comparing MSE/NCC/MI within fROI/aROI, it shows that surrogate metrics over aROI instead of fROI significantly improve segmentation performance, while there is no statistical evidence to support the superiority among MSE/NCC/MI.
SU‐D‐18C‐01: A Novel 4D‐MRI Technology Based On K‐Space Retrospective Sorting
Authors: Liu Y , Yin F , Cai J
Published: July 2014

Purpose:

Current 4D‐MRI techniques lack sufficient temporal/spatial resolution and consistent tumor contrast. To overcome these limitations, this study presents the development and initial evaluation of an entirely new framework of 4D‐MRI based on k‐space retrospective sorting.

Methods:

An important challenge of the proposed technique is to determine the number of repeated scans(NR) required to obtain sufficient k‐space data for 4D‐MRI. To do that, simulations using 29 cancer patients' respiratory profiles were performed to derive the relationship between data acquisition completeness(Cp) and NR, also relationship between NR(Cp=95%) and the following factors: total slice(NS), respiratory phase bin length(Lb), frame rate(fr), resolution(R) and image acquisition starting‐phase(P0). To evaluate our technique, a computer simulation study on a 4D digital human phantom (XCAT) were conducted with regular breathing (fr=0.5Hz; R=256×256). A 2D echo planer imaging(EPI) MRI sequence were assumed to acquire raw k‐space data, with respiratory signal and acquisition time for each k‐space data line recorded simultaneously. K‐space data was re‐sorted based on respiratory phases. To evaluate 4D‐MRI image quality, tumor trajectories were measured and compared with the input signal. Mean relative amplitude difference(D) and cross‐correlation coefficient(CC) are calculated. Finally, phase‐sharing sliding window technique was applied to investigate the feasibility of generating ultra‐fast 4D‐MRI.

Result:

Cp increased with NR(Cp=100*[1‐exp(‐0.19*NR)], when NS=30, Lb=100%/6). NR(Cp=95%) was inversely‐proportional to Lb (r=0.97), but independent of other factors. 4D‐MRI on XCAT demonstrated highly accurate motion information (D=0.67%, CC=0.996) with much less artifacts than those on image‐based sorting 4D‐MRI. Ultra‐fast 4D‐MRI with an apparent temporal resolution of 10 frames/second was reconstructed using the phase‐sharing sliding window technique.

Conclusions:

A novel 4D‐MRI technology based on k‐space sorting has been successfully developed and evaluated on the digital phantom. Framework established can be applied to a variety of MR sequences, showing great promises to develop the optimal 4D‐MRI technique for many radiation therapy applications.

NIH (1R21CA165384‐01A1)