bluuebunny/crossref_metadata_2025 huggingface dataset:
Development and application of a new measure of engagement in out‐patient HIV care
Authors: Howarth AR , Burns FM , Apea V , Jose S , Hill T , Delpech VC , Evans A , Mercer CH , Michie S , Morris S , Sachikonye M , Sabin C ,   the REACH study,   the UK Collaborative HIV Cohort (UK CHIC) study
Published: August 2016

Objectives

Commonly used measures of engagement in HIV care do not take into account that the frequency of attendance is related to changes in treatment and health status. This study developed a new measure of engagement in care (EIC) incorporating clinical factors.

Methods

We conducted semi‐structured interviews with eight HIV physicians to identify factors associated with the timing of patients' next scheduled appointments. These factors informed the development of an algorithm to classify each month of follow‐up as “in care” (on or before the time of the next expected attendance) or “out of care” (after the time of the next expected attendance). The EIC algorithm was applied to data from the UK Collaborative HIV Cohort (UK CHIC) study, a large clinical cohort study.

Results

The interviews indicated that time to next appointment varied depending on psychosocial and physical comorbidities, and clinical factors (time since diagnosis, AIDS diagnosis, treatment status, CD4 count and viral load). The resulting EIC algorithm was applied to 44 432 patients; 83.9% of the 3 021 224 person‐months were “in care”. Greater EIC was independently associated with older age, white ethnicity, HIV acquisition through sex between men, current use of antiretroviral therapy (ART), a higher nadir CD4 count, later calendar year and being seen at the clinic for the first time within the last year.

Conclusions

This algorithm describing engagement in HIV care incorporates a time‐updated measure of patients' treatment and health status. It adds to the options available for measuring this key performance indicator.
Evaluation of HIV testing recommendations in specialty guidelines for the management of HIV indicator conditions
Authors: Lord E , Stockdale AJ , Malek R , Rae C , Sperle I , Raben D , Freedman A , Churchill D , Lundgren J , Sullivan AK ,   the British Association of Sexual Health HIV (BASHH)/British HIV Association (BHIVA) guideline review group for the Optimising Testing and Linkage to Care for HIV across Europe (OptTEST) project by HIV in Europe
Published: August 2016

Objectives

European guidelines recommend HIV testing for individuals presenting with indicator conditions (ICs) including AIDS‐defining conditions (ADCs). The extent to which non‐HIV specialty guidelines recommend HIV testing in ICs and ADCs is unknown. Our aim was to pilot a methodology in the UK to review specialty guidelines and ascertain if HIV was discussed and testing recommended.

Methods

UK and European HIV testing guidelines were reviewed to produce a list of 25 ADCs and 49 ICs. UK guidelines for these conditions were identified from searches of the websites of specialist societies, the National Institute of Clinical Excellence (NICE) website, the NICE Clinical Knowledge Summaries (CKS) website, the Scottish Intercollegiate Guidance Network (SIGN) website and the British Medical Journal Best Practice database and from Google searches.

Results

We identified guidelines for 12 of 25 ADCs (48%) and 36 of 49 (73%) ICs. In total, 78 guidelines were reviewed (range 0–13 per condition). HIV testing was recommended in six of 17 ADC guidelines (35%) and 24 of 61 IC guidelines (39%). At least one guideline recommended HIV testing for six of 25 ADCs (24%) and 16 of 49 ICs (33%). There was no association between recommendation to test and publication year (P = 0.62).

Conclusions

The majority of guidelines for ICs do not recommend testing. Clinicians managing ICs may be unaware of recommendations produced by HIV societies or the prevalence of undiagnosed HIV infection among these patients. We are piloting methods to engage with guideline development groups to ensure that patients diagnosed with ICs/ADCs are tested for HIV. We then plan to apply our methodology in other European settings as part of the Optimising Testing and Linkage to Care for HIV across Europe (OptTEST) project.
Pulmonary Vein Isolation Using a Second‐Generation Cryoballoon in Patients With Paroxysmal Atrial Fibrillation: One‐Year Outcome Using a Single Big‐Balloon 3‐Minute Freeze Technique
Authors: MIYAZAKI SHINSUKE , HACHIYA HITOSHI , NAKAMURA HIROAKI , TANIGUCHI HIROSHI , TAKAGI TAKAMITSU , HIRAO KENZO , IESAKA YOSHITO
Published: August 2016

Cryoballoon Ablation of PAF

Background

The second‐generation cryoballoon (CB) has been recently introduced into clinical use for pulmonary vein isolation (PVI). Data on the feasibility, long‐term outcome, and optimal freeze cycle are still limited. We assessed the 1‐year clinical outcome after second‐generation CB ablation with single 3‐minute freeze techniques, and clinical variables associated with AF recurrence.

Methods

A total of 108 paroxysmal atrial fibrillation (PAF) patients undergoing cryothermal PVI were enrolled. PVI was performed with one 28‐mm CB using single 3‐minute freeze techniques without bonus applications. Fourteen‐day consecutive monitoring was done after discharge to detect early AF recurrences (ERAFs).

Results

Out of 425 PVs, 409 (96.2%) were isolated using exclusively CBs, and 16 required touch‐up ablation. Transient phrenic nerve injury, pericardial tamponade, and 50% PV stenosis occurred in 9, 1, and 1 patients, respectively. No PV stenosis >50% was observed in any patients. The total procedure and fluoroscopic times were 82.9 ± 26.4 and 26.2 ± 14.8 minutes, respectively. ERAFs were detected in 51 (47.2%) patients. At 1‐year after single and repeat procedures, 71.6% and 84.3% of the patients were free from recurrent AF off antiarrhythmic drugs (AADs), respectively. Eighteen patients underwent repeat procedures (median 6.0 [4.0–9.3] months post procedure), and 68.6% of PVs were still isolated. Cox's proportional models determined that ERAFs were significantly associated with AF recurrence (HR = 7.236; 95%CI = 2.753–19.016; P < 0.0001). AF‐freedom off AADs at 1‐year after single procedures was 90.8% and 50.3% in patients without and with ERAFs.

Conclusions

Second‐generation CB ablation using single 3‐minute freeze techniques appears feasible in PAF patients. ERAFs were significant factors for predicting clinical outcomes.
Upholding Shared Values in the EU: What Role for the EU Agency for Fundamental Rights?
Authors: Toggenburg Gabriel N. , Grimheden Jonas
Published: August 2016

Respect for the values laid down in Article 2 of the Treaty on European Union (TEU) was one of the primary reasons that led to the establishment of the European Union Agency for Fundamental Rights (FRA). While neither the Treaties nor the Regulation establishing FRA envisage an explicit role for the FRA with respect to Article 7 TEU, its assistance may be sought in this context even though the contours of such an eventual assistance remains to be clarified. By contrast, the European Commission may approach the FRA should the Commission require its assistance with respect to the application of the framework it adopted in 2014. The Council and the Parliament could similarly require the FRA's assistance. It is however submitted that a more structured dialogue and the regular provision of data and analysis, including via the FRA, would make the EU system of monitoring respect for EU values within the EU itself more operational and help prevent double standards.
The effect of the application of manual pressure before the administration of intramuscular injections on students' perceptions of postinjection pain: a semi‐experimental study
Authors: Öztürk Deniz , Baykara Zehra Gocmen , Karadag Ayise , Eyikara Evrim
Published: August 2016

Aims and objectives

To evaluate the efficacy of applying manual pressure before intramuscular injection and compare it with the standard injection technique in terms of reducing the young adult student's postinjection pain.

Background

The administration of intramuscular injections is a procedure performed by nurses and one that causes anxiety and pain for the patient. Nurses have ethical and legal obligations to mitigate injection‐related pain and the nurses' use of effective pain management not only provides physical comfort to the patients, but also improves the patients' experience.

Design

Comparative experimental study.

Methods

This study was conducted with first‐year university students (n = 123) who were scheduled for hepatitis A and hepatitis B vaccination via deltoid muscle injection. Students were randomly assigned to the groups. Comparison group students (n = 60) were given an injection using the conventional method, that is without manual pressure being applied prior to the injection. The experimental group students (n = 63) received manual pressure at the vaccination site immediately before injection for a period of 10 seconds. The two techniques were used randomly. The subjects were given pressure to the injection site, and perceived pain intensity was measured using Numerical Rating Scale.

Results

Findings demonstrate that students experienced significantly less pain when they received injections with manual pressure compared with the standard injection technique. The postinjection average pain score in the comparison group was higher than that in the experimental group (p < 0·05).

Conclusions

This study's results show that the application of manual pressure to the injection site before intramuscular injections reduces postinjection pain intensity in young adult students (p < 0·05). Based on these results before the injection, applying manual pressure to the adult's intramuscular injection site is recommended.

Relevance to clinical practice

Applying pressure to the injection area is a simple and cost‐effective method to reduce the pain associated with injection.
Facial weakness in a newborn
Authors: Rashid Salman , Hanba Curtis , Agarwal Rajkumar
Published: August 2016

See Answer
Diversifying selection is the dominant factor affecting the geographical variation of MHC class II genes in the Omei tree frog
Authors: Li J. , Shen H. , Wang H. , Zhao M. , Luo Z. , Wu H.
Published: August 2016

Genes encoding the major histocompatibility complex (MHC) are excellent candidates for elucidating adaptive variation because of their essential role in immune function. Hypotheses for how genetic variations of MHC genes are maintained include balancing selection, diversifying selection and neutral events; however, which of these forces are dominant remains controversial. In this study, we determined the preliminary forces that shaped MHC geographical variation in Omei tree frog by comparing with neutral microsatellites. The results revealed high genetic diversity and significant population differentiation in MHC genes of this species. The differentiation patterns of MHC and microsatellites were uncorrelated. Stronger level of genetic differentiation in MHC genes compared with that in microsatellites (based on comparison in both genetic differentiation patterns and strength of isolation by distance patterns) indicates the effects of diversifying selection on the geographical variation of MHC genes. Considering the significant evidence of positive selection acting on antigen‐binding sites, we presumed that selection pressures may be mainly from locally different pathogens when gene flow is restricted. The results of this study contribute to a more comprehensive understanding of the evolutionary forces that maintain MHC geographical variation among natural populations.
Distinguishing Arctic charr with different stress coping styles by visual screening of spottiness – reliability and consistency over time
Authors: Brännäs E. , Backström T. , Nilsson J. , Carlberg H. , Stien L. H. , Magnhagen C.
Published: August 2016

The salmonid fish Arctic charr Salvelinus alpinus shows pronounced individual variation in skin colouration and density of carotenoid‐based spots. It has earlier been shown that spot density is a heritable trait, and may be used as an indicator of stress coping style in Arctic charr. Individuals with few spots tend to be more aggressive and less responsive to stress (proactive) than those with many spots (reactive). Here, we evaluate the potential of grading individuals into proactive and reactive individuals by the density of light‐coloured spots. This non‐invasive method would be useful for selective breeding and to reduce within‐treatment variation in biological research. Our aim was to investigate stability of spot density over time and to compare methods to estimate spottiness on Arctic charr, using photographs as well as live fish. The consistency of spot density was significant over a period of 8 months, but with stronger correlations between September and December than between May and September. Also, repeatability of spot number was higher between the two last months than when including May. The spots were more stable on the left than the right side, thus, it is more reliable to estimate spottiness on the left side. There was a significant relationship between the ratio of spotted area (rsa) from automated image analysis and number of spots from visual counts. Both methods fitted well into a visual grading into three categories (few, medium and many spots). In another test, a large number of live fish were visually categorized according to spot density. The previous validation process, in combination with a significant family effect showed that large numbers of fish can be effectively graded.
Plasticity and consistency of behavioural responses to predation risk in laboratory environments
Authors: Heynen M. , Borcherding J. , Bunnefeld N. , Magnhagen C.
Published: August 2016

The individual animal is currently a major focus of behavioural research and an increasing number of studies raise the question of how between‐individual behavioural consistency and behavioural plasticity interact. Applying the reaction norm concept on groups, our study addresses both of these aspects in one framework and within an animal's natural social environment. Risk‐taking behaviour in 1‐year‐old perch Perca fluviatilis was assayed in aquarium experiments before and after the fish were subjected to the presence or absence of a piscivorous predator for 3 weeks. To analyse the inter‐individual behavioural variation across the repeated measurements, we dissected the behavioural change across the predator treatment into individual constant and plastic components using hierarchical mixed‐effects models. During the predator treatment, juvenile perch increased in boldness and decreased in vigilance, the magnitude of these behavioural changes was influenced by group composition. However, the behavioural changes were not influenced by the presence of a predator, indicating the difficulties in generating realistic long‐term predation pressure in the laboratory. Individuals differed in the relative increase in boldness across the predator treatment and, thus, varied in the shape of their reaction norms. In accordance, the best linear unbiased predictors, extracted from the random effects of separate linear mixed‐effects models for the data before and after the predator treatment were only weakly correlated. Hence, between‐individual variation seems to change under laboratory conditions and therewith not necessarily represents the initially present ‘natural’ variation, giving important implications for the conduction and interpretation of behavioural experiments.
Density dependence, climate and fires determine population fluctuations of the spur‐thighed tortoiseTestudo graeca
Authors: Rodríguez‐Caro R. C. , Lima M. , Anadón J. D. , Graciá E. , Giménez A.
Published: August 2016

Population fluctuations are driven by a combination of multiple factors, which can be classified into endogenous and exogenous. Endogenous factors are directly related to density‐dependent forces, whereas exogenous factors are environmental drivers (e.g. climate). Several studies have reported the effects of endogenous and exogenous factors using exponential population models in mammals, birds or insects, but few works have explored the effects on reptiles, specifically in tortoises. In this study, we developed logistic population growth models to decipher the role of these factors on the population dynamics of the spur‐thighed tortoiseTestudo graeca. The role of environmental drivers in the distribution, movement, survival, reproduction or individual growth has been described for this species in previous works, but no studies have examined the effects of both endogenous and exogenous factors in population growth rates. Using long‐term data ofT. graecain southeastern Iberian Peninsula (1999–2013), we fitted non‐linear logistic models with endogenous and exogenous effects. The results showed that endogenous processes are important drivers of the population dynamics of this species, and that exogenous factors, such as freezing hours in winter, also directly affect the population growth rate. Intolerance of extreme winter temperatures may especially affect hatchlings and juvenile tortoises. Our models also showed that perturbations (i.e. a fire occurred during the monitoring period) have a lasting impact by reducing the carrying capacity of the population. This study shows that simple quantitative approaches based on population dynamic theory are useful for deciphering the ecological mechanisms underlying dynamics of tortoise populations.
The value of life in English law: revered but not sacred?
Authors: Heywood Rob , Mullock Alexandra
Published: August 2016

Terms such as sanctity and inviolability have failed to provide a legally coherent or ethically sound principle upon which to determine the scope of the intrinsic value of life against extrinsic, quality-of-life considerations in a medical context. In their recent work, Margaret Brazier and Suzanne Ost introduce a new term, reverence for life, which they suggest may be more appropriate when attempting to navigate the murky waters of the meaning of life and the value that should be attached to it. They suggest that reverence should be utilised as an alternative that better reflects the nuances and the realities of the dilemma. This paper explores the existing difficulties before considering how the principle of reverence might provide a principled compromise over when the presumption in favour of preserving life should be rebutted.
Prognostic relevance of miR‐137 in patients with hepatocellular carcinoma
Authors: Sakabe Tomohiko , Azumi Junya , Umekita Yoshihisa , Toriguchi Kan , Hatano Etsuro , Hirooka Yasuaki , Shiota Goshi
Published: August 2016

Background & Aims

Cancer stem cells (CSCs) play a pivotal role in progression, metastasis and recurrence of cancer. Therefore, it is clinically useful to identify the relevant CSC marker that is associated with prognosis of hepatocellular carcinoma (HCC) and clarify its genetic and biological characteristics.

Methods

Expression of four CSC markers, CD13, EpCAM, CD44 and CD44v9, was examined in 99 HCC patients. Biological and cDNA/miRNA microarray data were compared among CD44‐positive/‐negative HCC cells and normal hepatic cells. The significance of the representative miRNAs was examined with regard to prognosis of additional 110 HCC patients.

Results

CD44‐positive HuH7 cells proliferated faster and showed a greater sphere forming ability than CD44‐negative HuH7 cells. CD44‐positive HuH7 cells exhibited higher expression of specific genes involved in resistance to reactive oxygen species, anticancer drugs and tumour invasion than CD44‐negative HCC cells. Higher expression of six miRNAs was observed in CD44‐positive HuH7 cells, CD44‐negative HuH7 cells, and human normal hepatic cells in that order. Of the six miRNAs, miR‐137 was closely associated with overall and cancer‐specific survivals, as well as with invasion of hepatic vein, hepatic artery, portal vein and bile duct, and alpha‐foetoprotein in additional 110 HCC patients.

Conclusions

miR‐137 may serve as a prognostic marker in patients with HCC and may be a potential target for the elimination of liver CSCs.
A user‐friendly means to scale from the biochemistry of photosynthesis to whole crop canopies and production in time and space – development of Java WIMOVAC
Authors: Song Qingfeng , Chen Dairui , Long Stephen P. , Zhu Xin‐Guang
Published: August 2016

Windows Intuitive Model of Vegetation response to Atmosphere and Climate Change (WIMOVAC) has been used widely as a generic modular mechanistically rich model of plant production. It can predict the responses of leaf and canopy carbon balance, as well as production in different environmental conditions, in particular those relevant to global change. Here, we introduce an open source Java user‐friendly version of WIMOVAC. This software is platform independent and can be easily downloaded to a laptop and used without any prior programming skills. In this article, we describe the structure, equations and user guide and illustrate some potential applications of WIMOVAC.
Safety of Bifidobacterium breve (BBG‐01) in preterm infants
Authors: Kitajima Hiroyuki , Hirano Shinya
Published: August 2016

Background

Since 1982, viable cells of Bifidobacterium breve (BBG‐01) have been used in pediatric patients for clinical conditions such as intractable infantile diarrhea, preterm status, and pediatric surgery. Although the efficacy of BBG‐01 has been widely reported, adverse events related to the use of BBG‐01 have been reported in very few cases.

Methods

In order to trace adverse events seen by 109 doctors in 88 medical institutions where BBG‐01 was used, a questionnaire survey of the number of occurrences and details of each case was conducted.

Results

Eighty‐six clinicians (70 institutions) responded to the questionnaire (response rate, 78.9%). Number of respondents according to department of diagnosis (no. BBG‐01‐treated infants) was as follows: pediatrics, 29 respondents (10 938 patients); premature and newborn medicine, 26 (10 677 patients); obstetrics and gynecology, 1 (1212 patients) and pediatric surgery, 22 (169 patients). More than 90% of the total BBG‐01‐treated patients (23 092 patients) were in the departments of premature and newborn medicine and pediatrics, and BBG‐01 had been used mainly in preterm infants and children with intractable diarrhea. Adverse events occurred in two extremely premature infants with functional ileus due to starch aggregates as vehicle, and in two surgical neonates with bacteremia caused by B. breve genetically identical to BBG‐01, and no serious adverse events with poor outcome were reported.

Conclusion

Adverse events related to the use of BBG‐01 have an extremely low incidence and are mild in severity, thus ensuring the superior safety of this preparation.
The human CO2 market
Authors: Rodenstein Daniel
Published: August 2016

See article, page 1300
Bronchoarterial ratio in never‐smokers adults: Implications for bronchial dilation definition
Authors: Diaz Alejandro A. , Young Thomas P. , Maselli Diego J. , Martinez Carlos H. , Maclean Erick S. , Yen Andrew , Dass Chandra , Simpson Scott A. , Lynch David A. , Kinney Gregory L. , Hokanson John E. , Washko George R. , San José Estépar Raul
Published: August 2016

ABSTRACT

Background and objective

Bronchiectasis manifests as recurrent respiratory infections and reduced lung function. Airway dilation, which is measured as the ratio of the diameters of the bronchial lumen (B) and adjacent pulmonary artery (A), is a defining radiological feature of bronchiectasis. A challenge to equating the bronchoarterial (BA) ratio to disease severity is that the diameters of airway and vessel in health are not established. We sought to explore the variability of BA ratio in never‐smokers without pulmonary disease and its associations with lung function.

Methods

Objective measurements of the BA ratio on volumetric computed tomography (CT) scans and pulmonary function data were collected in 106 never‐smokers. The BA ratio was measured in the right upper lobe apical bronchus (RB1) and the right lower lobe basal posterior bronchus. The association between the BA ratio and forced expiratory volume in 1 s (FEV1
) was assessed using regression analysis.

Results

The BA ratio was 0.79 ± 0.16 and was smaller in more peripheral RB1 bronchi (P < 0.0001). The BA ratio was >1, a typical threshold for bronchiectasis, in 10 (8.5%) subjects. Subjects with a BA ratio >1 versus ≤1 had smaller artery diameters (P < 0.0001) but not significantly larger bronchial lumens. After adjusting for age, gender, race and height, the BA ratio was directly related to FEV1
(P = 0.0007).

Conclusion

In never‐smokers, the BA ratio varies by airway generation and is associated with lung function. A BA ratio >1 is driven by small arteries. Using artery diameter as reference to define bronchial dilation seems inappropriate.
Rethinking the Meaning of Concentration–Response Functions and the Estimated Burden of Adverse Health Effects Attributed to Exposure Concentrations
Authors: (Tony) Cox Louis Anthony
Published: August 2016

Four articles by Anenberg et al., Fann et al., Shin et al., and Smith contribute valuable perspectives and syntheses to a large and growing literature that estimates the burden of mortality risks attributed to fine particulate matter (PM2.5) based on estimated epidemiological associations, summarized as concentration–response (C–R) relations. This comment questions the use of C–R relations to predict or estimate how changing exposure concentrations would change responses in a population. C–R associations typically reflect modeling choices, and equally good choices can commonly lead to conflicting conclusions about the signs, significance, and magnitudes of C–R relations and regression coefficients. This indicates that C–R relations do not necessarily reflect underlying stable causal laws useful for making risk predictions, but only choices about how to describe past data, with no uniquely correct choice being determined by the data. Similarly, currently available C–R data typically do not suffice to make valid predictions about how future changes in concentrations will affect responses. These difficulties can be substantially overcome by model ensemble and causal graph modeling and time series methods, but these require different data and knowledge—for example, knowledge of how multiple variables depend on each other, rather than only of how one dependent variable is associated with multiple explanatory variables—than that captured by traditional C–R models or expressible by any single C–R coefficient or curve.
Imposing Cognitive Constraints on Reference Production: The Interplay Between Speech and Gesture During Grounding
Authors: Masson‐Carro Ingrid , Goudbeek Martijn , Krahmer Emiel
Published: August 2016

Past research has sought to elucidate how speakers and addressees establish common ground in conversation, yet few studies have focused on how visual cues such as co‐speech gestures contribute to this process. Likewise, the effect of cognitive constraints on multimodal grounding remains to be established. This study addresses the relationship between the verbal and gestural modalities during grounding in referential communication. We report data from a collaborative task where repeated references were elicited, and a time constraint was imposed to increase cognitive load. Our results reveal no differential effects of repetition or cognitive load on the semantic‐based gesture rate, suggesting that representational gestures and speech are closely coordinated during grounding. However, gestures and speech differed in their execution, especially under time pressure. We argue that speech and gesture are two complementary streams that might be planned in conjunction but that unfold independently in later stages of language production, with speakers emphasizing the form of their gestures, but not of their words, to better meet the goals of the collaborative task.
Marked hyperphosphatasemia associated with an acute leukemia in a Great Dane
Authors: Froment Rémi , Bédard Christian
Published: August 2016

This is the report of a 5‐year‐old male neutered Great Dane with an extreme leukocytosis (544.9 × 109 cells/L; RI 5.2–13.9 × 109 cells/L) characterized by highly atypical round cells. Cellular morphologic features such as cytoplasmic membrane blebs, a high nuclear‐to‐cytoplasmic ratio, and nuclear indentations and irregularities and large nucleoli, as well as immunocytochemistry for CD3 and CD79, myeloperoxidase cytochemistry, and clonality testing were not conclusive for myeloid or lymphoid origin. Marked alkaline hyperphosphatasemia was present at the first visit (2783.0 U/L; RI 6–80.0 U/L), followed by a 5‐fold increase (14,000 U/L) a week later, identified as being mostly contributed by the bone‐ALP isoform (11,062 U/L; RI 0–30 U/L). In addition, the atypical leukocytes were strongly positive for cytoplasmic ALP activity. In vitro lysis of a heparin blood sample resulted in a 1.7‐fold increase of ALP activity, supporting the origin of the hyperphosphatasemia at least in part from the leukemic cell population. To the authors’ knowledge, this is a unique case of alkaline hyperphosphatasemia, due at least to a leukemic cell population producing a bone‐ALP isoform, regardless of the exact nature of the leukemia.
Innovation of Irradiation Equipment at the LVR-15 Nuclear Research Reactor
Authors: Lahodová Zdena , Soukupová Witolda , Koleška Michal , Ernest Jaroslav , Zmítková Jelena
Published: August 2016

This paper describes the design and use of a new irradiation facility for the LVR-15 nuclear research reactor. The CHOUCA MT irradiation rig was produced in France according to a design of the ÚJV Group (ÚJV Řež and Research Center Řež). There are six heating sections situated along the rig, each instrumented and controlled by its own thermocouple. The rig’s insulation layers ensure a balanced temperature in irradiated specimens along its entire length. The specimen holder is 55.9 mm in diameter and 320 mm long. The CHOUCA MT rig can be repetitively irradiated in different positions within the reactor core, depending on irradiation condition requirements. The CHOUCA MT rig expands the possibilities of radiation research in the ÚJV Group.
Numerical Analysis of Microstructure and Residual Stress in the Weld Zone of Multiwire Submerged Arc Welding
Authors: Yu Enlin , Han Yi , Xiao Haixiang , Gao Ying
Published: August 2016

As oil and gas pipelines develop toward large throughput and high pressure, more and more attention has been paid to welding quality of oil pipelines. Submerged arc welding is widely applied in manufacturing of large-diameter welded pipes, and the welding quality has an impact on pipeline safety. With a multiwire submerged arc welding test platform and real-time temperature measurement system, temperature measurement has been done for multiwire submerged arc welding process with and without flux coverage, respectively. As a result, thermal cycling curves in both cases have been obtained, and convection and radiation coefficients of flux-covered X80 pipeline steel in air-cooled environment have been corrected. By using sysweld software, a finite-element computational model was set up for microstructure and residual stress in the weld zone of multiwire longitudinal submerged arc welding. Comparative experiment has been done to obtain welding temperature field with relatively high accuracy. Calculation and analysis of residual stress versus preheat residual stress decreased with increasing preheat temperature up to 100 °C, meanwhile content of bainite in microstructure fell, facilitating reduction in residual stress to some extent. This study provides quantitative reference for further optimization of welding parameters and improvement in weld mechanical properties.
A Modeling Approach to Study the Fluid-Dynamic Forces Acting on the Spool of a Flow Control Valve
Authors: Frosina Emma , Senatore Adolfo , Buono Dario , Stelson Kim A.
Published: August 2016

This paper introduces an approach to study a valve's internal fluid dynamics. During operation, the flow causes forces on the spool. These forces must be correctly balanced. Since these forces cannot be measured, a three-dimensional (3D) computational fluid dynamic (CFD) modeling approach is needed. A case study has been undertaken to verify the approach on a two-way pressure compensated flow control valve. Since forces vary during operation, the analysis must be transient. From the initial zero spool position, the flow goes through the valve causing a spool shift inside the valve's housing until the spool stops at its final position. Forces depend on the spring reaction, the inlet pressure force, the pressure force of the fluid inside the spool, and the spring holder volumes, and the balance of forces influences the outlet flow rate at the final spool position. First, the initial case geometry was modeled, prototyped, and tested, and this geometry was studied to verify the model accuracy compared to experimental data. The comparison shows good agreement with a maximum error of 3%. With the same approach, several other geometries were designed, but only the best geometry was prototyped and tested. The model was adopted to make several analyses of velocity contouring, streamlines trends, and pressure distribution in the fluid volume. The modeled and tested results achieved the expected performance confirming the effectiveness of the methodology.
Application of the Particle Finite Element Method in Machining Simulation Discussion of the Alpha-Shape Method in the Context of Strength of Materials
Authors: Sabel Matthias , Sator Christian , Zohdi Tarek I. , Müller Ralf
Published: August 2016

In particle finite element simulations, a continuous body is represented by a set of particles that carry all physical information of the body, such as the deformation. In order to form this body, the boundary of the particle set needs to be determined. This is accomplished by the α-shape method, where the crucial parameter α controls the level of detail of the detected shape. However, in solid mechanics, it can be observed that α has an influence on the structural integrity as well. In this paper, we study a single boundary segment of a body during a deformation and it is shown that α can be interpreted as the maximum stretch of this segment. On the continuum level, a relation between α and the eigenvalues of the right Cauchy–Green tensor is presented.
Sci‐Thur AM: YIS – 03: Combining sagittally‐reconstructed 3D and live‐2D ultrasound for high‐dose‐rate prostate brachytherapy needle segmentation
Authors: Hrinivich Thomas , Hoover Douglas , Surry Kathleen , Edirisinghe Chandima , D'Souza David , Fenster Aaron , Wong Eugene
Published: August 2016

Ultrasound‐guided high‐dose‐rate prostate brachytherapy (HDR‐BT) needle segmentation is performed clinically using live‐2D sagittal images. Organ segmentation is then performed using axial images, introducing a source of geometric uncertainty. Sagittally‐reconstructed 3D (SR3D) ultrasound enables both needle and organ segmentation, but suffers from shadow artifacts. We present a needle segmentation technique augmenting SR3D with live‐2D sagittal images using mechanical probe tracking to mitigate image artifacts and compare it to the clinical standard.

Seven prostate cancer patients underwent TRUS‐guided HDR‐BT during which the clinical and proposed segmentation techniques were completed in parallel using dual ultrasound video outputs. Calibrated needle end‐length measurements were used to calculate insertion depth errors (IDEs), and the dosimetric impact of IDEs was evaluated by perturbing clinical treatment plan source positions.

The proposed technique provided smaller IDEs than the clinical approach, with mean±SD of −0.3±2.2 mm and −0.5±3.7mm respectively. The proposed and clinical techniques resulted in 84% and 43% of needles with IDEs within ±3mm, and IDE ranges across all needles of [−7.7mm, 5.9mm] and [−9.3mm, 7.7mm] respectively. The proposed and clinical IDEs lead to mean±SD changes in the volume of the prostate receiving the prescription dose of −0.6±0.9% and −2.0±5.3% respectively.

The proposed technique provides improved HDR‐BT needle segmentation accuracy over the clinical technique leading to decreased dosimetric uncertainty by eliminating the axial‐to‐sagittal registration, and mitigates the effect of shadow artifacts by incorporating mechanically registered live‐2D sagittal images.
Sci‐Thur AM: YIS – 05: Prediction of lung tumor motion using a generalized neural network optimized from the average prediction outcome of a group of patients
Authors: Teo Troy , Alayoubi Nadia , Bruce Neil , Pistorius Stephen
Published: August 2016

Purpose:

In image‐guided adaptive radiotherapy systems, prediction of tumor motion is required to compensate for system latencies. However, due to the non‐stationary nature of respiration, it is a challenge to predict the associated tumor motions. In this work, a systematic design of the neural network (NN) using a mixture of online data acquired during the initial period of the tumor trajectory, coupled with a generalized model optimized using a group of patient data (obtained offline) is presented.

Methods:

The average error surface obtained from seven patients was used to determine the input data size and number of hidden neurons for the generalized NN. To reduce training time, instead of using random weights to initialize learning (method 1), weights inherited from previous training batches (method 2) were used to predict tumor position for each sliding window.

Results:

The generalized network was established with 35 input data (∼4.66s) and 20 hidden nodes. For a prediction horizon of 650 ms, mean absolute errors of 0.73 mm and 0.59 mm were obtained for method 1 and 2 respectively. An average initial learning period of 8.82 s is obtained.

Conclusions:

A network with a relatively short initial learning time was achieved. Its accuracy is comparable to previous studies. This network could be used as a plug‐and play predictor in which (a) tumor positions can be predicted as soon as treatment begins and (b) the need for pretreatment data and optimization for individual patients can be avoided.
Sci‐Thur AM: YIS – 06: A Monte Carlo study of macro‐ and microscopic dose descriptors and the microdosimetric spread using detailed cellular models
Authors: Oliver Patricia , Thomson Rowan
Published: August 2016

Purpose:

To develop Monte Carlo models of cell clusters to investigate the relationships between macro‐ and microscopic dose descriptors, quantify the microdosimetric spread in energy deposition for subcellular targets, and determine how these results depend on the computational model.

Methods:

Microscopic tissue structure is modelled as clusters of 13 to 150 cells, with cell (nuclear) radii between 5 and 10 microns (2 and 9 microns). Energy imparted per unit mass (specific energy or dose) is scored in the nucleus (Dnuc) and cytoplasm (Dcyt) for incident photon energies from 20 to 370 keV. Dose‐to‐water (Dw,m) and dose‐to‐medium (Dm,m) are compared to Dnuc and Dcyt. Single cells and single nuclear cavities are also simulated.

Results:

Dnuc and Dcyt are sensitive to the surrounding environment with deviations of up to 13% for a single nucleus/cell compared with a multicellular cluster. These dose descriptors vary with cell and nucleus size by up to 10%. Dnuc and Dcyt differ from Dw,m and Dm,m by up to 32%. The microdosimetric spread is sensitive to whether cells are arranged randomly or in a hexagonal lattice, and whether subcellular compartment sizes are sampled from a normal distribution or are constant throughout the cluster.

Conclusions:

Dnuc and Dcyt are sensitive to cell morphology, elemental composition and the presence of surrounding cells. The microdosimetric spread was investigated using realistic elemental compositions for the nucleus and cytoplasm, and depends strongly on subcellular compartment size, source energy and dose.
Sci‐Thur AM: YIS – 07: Optimizing dual‐energy x‐ray parameters using a single filter for both high and low‐energy images to enhance soft‐tissue imaging
Authors: Bowman Wesley , Sattarivand Mike
Published: August 2016

Objective:

To optimize dual‐energy parameters of ExacTrac stereoscopic x‐ray imaging system for lung SBRT patients

Methods:

Simulated spectra and a lung phantom were used to optimize filter material, thickness, kVps, and weighting factors to obtain bone subtracted dual‐energy images. Spektr simulations were used to identify material in the atomic number (Z) range [3–83] based on a metric defined to separate spectrums of high and low energies. Both energies used the same filter due to time constraints of image acquisition in lung SBRT imaging. A lung phantom containing bone, soft tissue, and a tumor mimicking material was imaged with filter thicknesses range [0–1] mm and kVp range [60–140]. A cost function based on contrast‐to‐noise‐ratio of bone, soft tissue, and tumor, as well as image noise content, was defined to optimize filter thickness and kVp. Using the optimized parameters, dual‐energy images of anthropomorphic Rando phantom were acquired and evaluated for bone subtraction. Imaging dose was measured with dual‐energy technique using tin filtering.

Results:

Tin was the material of choice providing the best energy separation, non‐toxicity, and non‐reactiveness. The best soft‐tissue‐only image in the lung phantom was obtained using 0.3 mm tin and [140, 80] kVp pair. Dual‐energy images of the Rando phantom had noticeable bone elimination when compared to no filtration. Dose was lower with tin filtering compared to no filtration.

Conclusions:

Dual‐energy soft‐tissue imaging is feasible using ExacTrac stereoscopic imaging system utilizing a single tin filter for both high and low energies and optimized acquisition parameters.
Sci‐Thur AM: YIS – 10: Modeling Metastasis after Lung SBRT Using Bayesian Network Averaging
Authors: Diamant André , Seuntjens Jan , El Naqa Issam , Ybarra Norma
Published: August 2016

Purpose:

The prediction of metastasis after a patient receives lung SBRT has proven to be challenging, due to the complex interactions between an individual's biology and dose‐volume metrics. The aim of this study is to use a Bayesian network approach to uncover possible interactions between an individual patient's characteristics and generate a robust model capable of predicting metastasis.

Methods:

We investigated a cohort of 32 prospective patients from multiple institutions whom had received curative SBRT to the lung. The number of patients exhibiting metastasis within 6 months of treatment was observed to be 6 (event rate of 19%). The serum concentration of 5 relevant biomarkers was measured pre‐treatment. A total of 21 variables were analyzed including: dose‐volume metrics with BED (biologically effective dose) correction and clinical variables. A Markov Chain Monte Carlo technique estimated the posterior probability distribution of the potential graphical structures. The probability of metastasis was then estimated by averaging the top 100 graphs and applying Baye's rule.

Results:

The optimal Bayesian model generated throughout this study incorporated the PTV volume, the serum concentration of the biomarker EGFR (epidermal growth factor receptor) and prescription BED. This predictive model recorded an area under the receiver operating characteristic curve of 0.94(1), providing better performance compared to competing methods in the literature.

Conclusion:

The use of biomarkers in conjunction with dose‐volume metrics allows for the generation of a robust predictive model. The results of this report demonstrate that it is possible to accurately model whether a patient will develop metastasis within 6 months of treatment.
Sci‐Thur PM – Colourful Interactions: Highlights 03: Radiation induced glycogen accumulation in non‐small cell lung cancer xenografts detected using Raman spectroscopy
Authors: Harder Samantha J. , Isabelle Martin , DeVorkin Lindsay , Smazynski Julian , Beckham Wayne , Brolo Alexandre , Lum Julian , Jirasek Andrew
Published: August 2016

Purpose:

This study presents the novel application of Raman spectroscopy (RS) to identify biochemical signatures of radiation response in human non‐small cell lung cancer (NSCLC) xenografts, irradiated in vivo.

Methods:

Human NSCLC cells (H460) were subcutaneously injected into the flanks of 12 mice. Tumours were treated with single fraction radiation doses (0, 5 or 15 Gy) and harvested at 3 days post irradiation. A Renishaw inVia Raman microscope coupled to a 785 nm laser was used to collect Raman spectral maps for each tumour. Immunohistochemistry (IHC) staining for CAIX was used to visualize hypoxia, and co‐registration between IHC fluorescence and Raman images was carried out.

Results:

Principal component analysis revealed radiation induced spectral signatures linked to changes in protein, nucleic acid, lipid and carbohydrates. In particular, a marked increase in glycogen for irradiated tumours was observed. Spatial mapping revealed intra‐tumoural heterogeneity in the distribution of glycogen within the tumour, suggesting tumour response to radiation is not globally uniform. Furthermore, co‐registration of Raman glycogen maps with CAIX IHC staining showed a correlation between glycogen rich and hypoxic regions of the tissue.

Conclusions:

We identify glycogen as a unique radiation induced response in NSCLC tumour xenografts, which may reflect inherent metabolic changes associated with radiation response in tissue. This study provides unique insight into the biochemical response of tumours, irradiated in vivo, and demonstrates the potential of RS for detecting radiobiological responses in tumours.
Sci‐Thur PM – Brachytherapy 04: Commissioning and Implementation of a Cobalt‐60 High Dose Rate Brachytherapy Source
Authors: Dysart Jonathan
Published: August 2016

An Eckert & Ziegler Bebig Co0.A86 cobalt 60 high dose rate (HDR) brachytherapy source was commissioned for clinical use. Long‐lived Co‐60 HDR sources offer potential logistical and economic advantages over Ir‐192 sources, and should be considered for low to medium workload brachytherapy departments where modest increases in treatment times are not a factor. In optimized plans, the Co‐60 source provides a similar dose distribution to Ir‐192 despite the difference in radiation energy. By switching to Co‐60, source exchange frequency can be reduced by a factor of 20, resulting in overall financial savings of more than 50% compared to Ir‐192 sources. In addition, a reduction in Physicist QA workload of roughly 200 hours over the 5 year life of the Co‐60 source is also expected. These benefits should be considered against the modest increases in average treatment time compared to those of Ir‐192 sources, as well as the centre‐specific needs for operating room shielding modification.