Simulations to design an online motion compensation system for scanned particle beams

Respiration-induced target motion is a major problem in intensity-modulated radiation therapy. Beam segments are delivered serially to form the total dose distribution. In the presence of motion, the spatial relation between dose deposition from different segments will be lost. Usually, this results in over-and underdosage. Besides such interplay effects between target motion and dynamic beam delivery as known from photon therapy, changes in internal density have an impact on delivered dose for intensity-modulated charged particle therapy. In this study, we have analysed interplay effects between raster scanned carbon ion beams and target motion. Furthermore, the potential of an online motion strategy was assessed in several simulations. An extended version of the clinical treatment planning software was used to calculate dose distributions to moving targets with and without motion compensation. For motion compensation, each individual ion pencil beam tracked the planned target position in the lateral aswell as longitudinal direction. Target translations and rotations, including changes in internal density, were simulated. Target motion simulating breathing resulted in severe degradation of delivered dose distributions. For example, for motion amplitudes of +/- 15 mm, only 47% of the target volume received 80% of the planned dose. Unpredictability of resulting dose distributions was demonstrated by varying motion parameters. On the other hand, motion compensation allowed for dose distributions for moving targets comparable to those for static targets. Even limited compensation precision (standard deviation similar to 2 mm), introduced to simulate possible limitations of real-time target tracking, resulted in less than 3% loss in dose homogeneity.

An online monitor ionization chamber used in particle therapy

The clinical trials of tumor therapy using heavy ions beam C-12 are now in progress at Institute of Modem Physics in Lanzhou. In order to achieve the precise radiotherapy with the high energy C-12 beam in active pencil beam scanning mode, we have developed an ionization chamber(IC) as an online monitor for beam intensity and also a dosimeter after calibration. Through the choosing of working gas and voltage, optimizing of the electrics and the read-out system, calibrating the linearity, the detector system provide us one of the simple and highly reliable way to monitoring the beam during the active pencil beam scanning treatments. The measurement results of this detector system show that it could work well under the condition of high energy C-12 beam in active pencil beam scanning mode.

maintaining only frequent itemsets to mine approximate frequent itemsets over online data streams

IEEE

Online study of the formation of PA6 droplets in PP matrix under shear flow

Breakup process of polyamide 6 (PA6) in polypropylene (PP) matrix under shear flow was online studied by using a Linkam CSS 450 stage equipped with optical microscopy. Both tip streaming and fracture breakup modes of PA6 droplets were observed in this study. It was reported that the droplet would break up by tip streaming model when the radio of the droplet phase viscosity to the matrix phase viscosity (n(r) = n(d)/n(m)) is smaller than 0.1 (Taylor, Proc R Soc London A 1934, 146, 501; Grace, Chem Eng Commun 1982, 14, 225; Bartok and Mason, J Colloid Sci 1959, 14, 13; Rumscheidt and Mason, J Colloid Sci 1961, 16, 238; de Bruijn, Chem Eng Sci 1993, 48, 277). However, the tip streaming model was observed even when the viscosity ratio was much greater than 0.1 (n(r) = 1.9). In this study for the tip streaming mode, small droplets were ruptured from the tip of the mother droplet. On the other hand, the mother droplet was broken into two or more daughter droplets with one or several satellite droplets between them for the fracture mode. It was found that PA6 droplet was much elongated at first, and then broke up via tip streaming or fracture to form daughter droplets or small satellite droplets with the shape of fiber or ellipse.

Analysis of primary aromatic amines using precolumn derivatization by HPLC fluorescence detection and online MS identification

2-(2-Phenyl-1H-phenanthro-[9,10-d]imidazole-1-yl)-acetic acid (PPIA) and 2-(9-acridone)-acetic acid (AAA), two novel precolumn fluorescent derivatization reagents, have been developed and compared for analysis of primary aromatic amines by high performance liquid chromatographic fluorescence detection coupled with online mass spectrometric identification. PPIA and AAA react rapidly and smoothly with the aromatic amines on the basis of a condensation reaction using 1-ethyl-3-(3dimethylaminopropyl)-carbodiimide (EDC) as dehydrating catalyst to form stable derivatives with emission wavelengths at 380 and 440 nm, respectively. Taking six primary aromatic amines (aniline, 2-methylaniline, 2-methoxyaniline, 4-methylaniline, 4-chloroaniline, and 4-bromoaniline) as testing compounds, derivatization conditions such as coupling reagent, basic catalyst, reaction temperature and time, reaction solvent, and fluorescent labeling reagent concentration have also been investigated. With the better PPIA method, chromatographic separation of derivatized aromatic amines exhibited a good baseline resolution on an RP column. At the same time, by online mass spectrometric identification with atmospheric pressure chemical ionization (APCI) source in positive ion mode, the PPIA-labeled derivatives were characterized by easy-to-interpret mass spectra due to the prominent protonated molecular ion m/z [M + H](+) and specific fragment ions (MS/MS) m/z 335 and 295. The linear range is 24.41 fmol-200.0 pmol with correlation coefficients in the range of 0.9996-0.9999, and detection limits of PPIA-labeled aromatic amines are 0.12-0.21 nmol/L (S/N = 3). Method repeatability, precision, and recovery were evaluated and the results were excellent for the efficient HPLC analysis. The most important argument, however, was the high sensitivity and ease-of-handling of the PPIA method. Preliminary experiments with wastewater samples collected from the waterspout of a paper mill and its nearby soil where pollution with aromatic amines may be expected show that the method is highly validated with little interference in the chromatogram.

Determination of free fatty acids in bryophyte plants and soil by HPLC with fluorescence detection and identification by online MS

A method for the determination of long and short chain free fatty acids (FFAs), using 1-[2-(ptoluenesulfonate)-ethyll-2-phenylimidazole-[4,5-f-9,10-phenanthrene (TSPP) as labeling reagent, has been developed. Identification of FFA derivatives was carried out by HPLC-MS with atmospheric pressure chemical ionization (APCI) in positive ion mode. Gradient elution on an Agilent Eclipse XDB-C-8 column gave good separation of the derivatives. Excellent linear responses were observed and good compositional data could be obtained from as little as 200 mg of bryophyte plants and soil samples. Facile TSPP derivatization coupled with HPLC-APCI-MS analysis allowed the development of a highly sensitive method for the quantitative analysis of trace level of FFAs from biological and natural environmental samples.

CPO - Carteira de projetos online.

2008

AINFO 2001: manual online.

Conhecendo o AINFO 2001. Gerenciador de dados AINFO 2001. Operando o AINFO 2001. Atualizando as bases de dados. Sobre as bases de dados. Gerando e imprimindo relatórios. Sobre o SIR - Recuperação da Informação. Descrição dos campos. Descrição dos campos. Descrição dos relatórios.

Reconceptualising moderation in asynchronous online discussions using grounded theory.

This paper reports a grounded theory study of e-moderation of asynchronous online discussions, to explore the processes by which tutors in higher education decide when and how to e-moderate. It aims to construct a theory of e-moderation based on some key factors which appear to influence e-moderation. It discusses previous research on the definition and practice of e-moderation, and then describes the study, which involved four e-moderators working in two different university contexts. Key themes on e-moderation, which emerged using a grounded theory approach, are discussed. It proposes a paradigm framework for e-moderation and suggests that as a facilitative activity, it should be sufficiently contained within ‘a ring-fenced learning arena’. Factors outwith and inside the ring-fence which appear to influence e-moderation and their implications for future theory development and validation are discussed. Keywords: e-moderation; grounded theory; online learning; asynchronous discussions; ring-fence

Community Councils online: a survey.

A survey of Scottish Community Councils found that only 22% have up-to-date online public presences. Only 4% of Community Councils have easily accessible online planning content. Most Community Councils websites communicate from Community Councils to citizen – only 10% use social media to host online discussion and opinion-gathering. Local Authority-hosted presences guarantee that Community Councils have presence but not that they are up to date. Such presences are also not content-rich. Community Councils’ own volition makes the difference between having no presence at all, mediocre presences and informative, content-rich presences that may serve citizens well. Suggestions to improve matters include broadening the scope of Local Authority-hosted presences and CCs mentoring each other.

Scottish Community Councils online: the 2014 survey.

This document reports the results of a survey, carried out in late spring 2014, of the public web presences of potentially over 1300 Scottish Community Councils (CCs). It follows on from similar survey in summer 2012. The report reviews content-types associated with up-to-date presences and examines Community Councils’ social media use, using three archetypes which may be used to derive models and examples of good practice, and create recommendations for Community Councils and their Local Authorities (LAs). The research found that there has little change overall since 2012, which combined with a high level of churn implies an increasing number of digitally disengaged Community Councils. A good way forward would be for to CCs emulate and adapt the examples of good practice identified, by publishing minutes, news, planning and local area information, limiting publication of other types of content, and using social media to engage with citizens. A number of broader recommendations are made to LAs, including that that they publish CC schemes on their websites, provide training in online methods and work together via their CCLOs and IT teams to support CCs

Local studies collections online: an investigation in Irish public libraries

Barry, L., Tedd, L.A. (2008). Local studies collections online: an investigation in Irish public libraries. Program: electronic library and information systems, 42(2), 163-186.

Who has the Right to Govern Online Activity? A Criminal and Civil Point of View

Kohl, U. (2004). Who has the right to govern online activity? A criminal and civil point of view. International Review of Law, Computers & Technology 18 (3), 387-410 RAE2008

Jurisdiction and the Internet: Regulatory Competence over Online Activity

null RAE2008