Nitrogen substitutional defects in silicon. A quantum mechanical investigation of the structural, electronic and vibrational properties

RD and FSG acknowledges the CINECA award (HP10CTG8YY) under the ISCRA initiative, for the availability of high performance computing resources and support.The vibrational infrared (IR) and Raman spectra of seven substitutional defects in bulk silicon are computed, by using the quantum mechanical CRYSTAL code, the supercell scheme, an all electron Gaussian type basis set and the B3LYP functional. The relative stability of various spin states has been evaluated, the geometry optimized, the electronic structure analyzed. The IR and Raman intensities have been evaluated analitically. In all cases the IR spectrum is dominated by a single N peak (or by two or three peaks with very close wavenumbers), whose intensity is at least 20 times larger than the one of any other peak. These peaks fall in the 645–712 cm−1 interval, and a shift of few cm−1 is observed from case to case. The Raman spectrum of all defects is dominated by an extremely intense peak at about 530 cm−1, resulting from the (weak) perturbation of the peak of pristine silicon.ISCRA initiative CINECA award (HP10CTG8YY); Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

Biological effects of high energy radiation and ultra high dose rates

Recently a powerful electron accelerator, 50 MeV race-track microtron, has been taken into clinical use. This gives the opportunity to treat patients with higher x-ray and electron energies than before. Furthermore, treatments can be performed were the entire fractional dose can be delivered in parts of a second. The relative biological effectiveness (RBE) of high energy photons (up to 50 MV) was studied in vitro and in vivo. Oxygen enhancement ratio (OER) of 50 MV photons and RBE of 50 MeV electrons were investigated in vitro. Single-fraction experiments, in vitro, using V-79 Chinese hamster fibroblasts showed an RBE for 50 MV x-rays of approximately 1.1 at surviving fraction 0.01, with reference to the response to 4 MV x- rays. No significant difference in OER could be demonstrated. Fractionation experiments were carried out to establish the RBE at the clinically relevant dose level, 2 Gy. The RBE calculated for the 2 Gy/fraction experiments was 1.17. The RBEs for 20 MV x-rays and 50 MeV electrons were equal to one. In order to investigate the validity of these results, the jejunal crypt microcolony assay in mice was used to determine the RBE of 50 MV x-rays. The RBE for 50 MV x-rays in this case was estimated to be 1.06 at crypt surviving fraction 0.1. Photonuclear processes are proposed as one possible explanation to the higher RBE for 50 MV x-rays. Several studies of biological response to ionizing radiation of high absorbed dose rates have been performed, often with conflicting results. With the aim of investigating whether a difference in effect between irradiation at high dose rates and at conventional dose rates could be verified, pulsed 50 MeV electrons from a clinical accelerator were used for experiments with ultra high dose rates (mean dose rate: 3.8 x 10^ Gy/s) in comparison to conventional (mean dose rate: 9.6 x 10"^ Gy/s). V-79 cells were irradiated in vitro under both oxic and anoxic conditions. No significant difference in relative biological effectiveness (RBE) or oxygen enhancement ratio (OER) was observed for ultra high dose rates compared to conventional dose rates. A central issue in clinical radiobiological research is the prediction of responses to different radiation qualities. The choice of cell survival and dose response model greatly influences the results. In this context the relationship between theory and model is emphasized. Generally, the interpretations of experimental data are dependent on the model. Cell survival models are systematized with respect to their relations to radiobiological theories of cell kill. The growing knowledge of biological, physical, and chemical mechanisms is reflected in the formulation of new models. This study shows that recent modelling has been more oriented towards the stochastic fluctuations connected to radiation energy deposition. This implies that the traditional cell survival models ought to be complemented by models of stochastic energy deposition processes at the intracellular level.S. 1-44: sammanfattning, s. 47-130: 5 uppsatserdigitalisering@um

Investigation of the prostate gland in different clinical conditions

Problems: Description of transrectal ultrasound (TRUS) anatomy in selected healthy men is lacking. Is the prostate gland involved in febrile urinary tract infection (UTI)? Is one negative prostate sextant-biopsy enough to rule out prostate cancer (PC)? What is the risk of diagnosing insignificant PC in men subjected to long-term PSA-screening?Methods: I) 125 healthy men (20-69 years) were investigated by TRUS. II-III) 70 and 55 men, respectively, with febrile UTI were followed 12 months with physical examinations, repeated PSA-testing and TRUS. IV-V) 10.000 men (50-65 years) were randomized to biennial PSA-screening. If elevated PSA digital rectal examination and TRUS-led prostate biopsies were recommended. In 457 men with one set of negative prostate-biopsies, the outcome from two subsequent screening-occasions was studied. The rate of low-volume PC (evaluated in prostatectomy- or biopsy-specimen) was studied in 544 men diagnosed at one of 4 biopsy-occasions. Results: I) Prostate volume (PV) increased with age (19.2-35.5cm3). Sonographic changes were common in all age-groups. II-III) 83% had elevated PSA (>4ng/ml) during febrile UTI. PV and decreased significantly (31%) the infection. Free-PSA normalized after one month. Complexed-PSA slowly decreased during 12 months. Up to six months free-to-total-PSA was similar to PC-values (11-16%). IV) Three groups were found: PC (26%), three negative biopsies (56%) and normalized PSA (17%). In cases with PV <20cm3 either PC or normalized PSA was found. Only follow-up identified the normalized-PSA group. V) Biopsies and cancers detected at four biopsy-rounds were; 1593/389, 571/120, 252/33 and 78/6, respectively. The risk of detecting low-volume cancer was constant (5-7%) at the different sets of biopsies, but the relative ratio of low-volume cancer doubled from 24% (19%) at primary biopsy to 48% (36%) at third biopsy. Conclusions: Various TRUS-findings are common among healthy men. The prostate gland is commonly involved in febrile UTI, with PSA and TRUS-findings during follow-up mimicking PC. Causes for PSA elevation in men with one negative sextant prostate-biopsy are PC, BPH and probably inflammation. The chance of finding significant cancer decreases with the number of previous sets of benign biopsies, while the risk of detecting low-volume cancer is constant

Refurbishment of hot dip galvanized products – environmental impacts in a life cycle perspective

This report contains a life cycle assessment of hot dip galvanized steel and refurbishment methods for hot dip galvanized steel. The purpose of the report is to investigate the environmental impact of different refurbishment methods and to compare the environmental impact of replacing hot-dip galvanized steel structures with maintenance of the corrosion protection of hot-dip galvanized steel structures. The analysis was carried out within the framework of an assignment performed for RISE KIMAB by Mats Zackrisson at RISE IVF, in the project Optimal maintenance of hot-dip galvanized products. Paint manufacturers, painting contractors, painting inspectors and researchers at RISE KIMAB have all contributed data and knowledge to the study. The results show that the pre-treatment and the zinc can give significant impacts for the refurbishment options. From a climate perspective, the results indicate that the refurbishment options need only prolong the life with 1-6 years, which, compared to the expected life extension 30 years indicates a large climate impact reduction potential with any of the refurbishment options. From an ozone formation perspective, the results indicate that the refurbishment options need to prolong the life with 3-33 years, which, compared to the expected life extension 30 years indicates that the right choice of refurbishment option is crucial in order to achieve potential ozone impact reductions with refurbishment. The practical corrosion tests carried out in the project will give more definite answers. The difference in potential impact between the refurbishment options should not be taken as absolute, since the information was mostly gathered from open sources, like safety data sheets and product information sheets. Nevertheless, the low (inherent) ozone formation impacts associated with the waterborne zinc silicate is worth mentioning, as well as Induraguard 9200´s environmentally benign pre-treatment (wire brushing). The study focuses on 8 mm thick steel structures. The thicker and heavier object, the more is, in general, to gain by refurbishing instead of replacing with new infrastructure object

Funktionsbaserad kravställning för rostskyddsmålning inom infrastrukturen Del 2-upphandlingsstrategier och tekniska krav

Med funktionsbaserad kravställning avses i detta arbete en blandning av funktionskrav och utförandekrav. Målet med en funktionsbaserad kravställning är att hitta ett optimum mellan funktionskrav och utförandekrav, så att introduktion av nya förbättrade produkter och produktionsmetoder underlättas utan att risken för misslyckanden blir alltför stora. De funktionskrav som beskrivs i denna rapport förväntas lämpa sig bäst för projekt där anbud på rostskyddet kan utvärderas separat. Sådana projekt kan vara nymålning eller komplett ommålning i projekt där målningsentreprenaden upphandlas separat. Att använda funktionskrav i nybyggnadsprojekt där målningen endast utgör en liten del av det totala projektet, riskerar att resultera i att rostskyddet får underordnad betydelse i anbudsutvärderingen. I detta arbete har vi definierat nio generella funktionsmål, vilka betraktas som oreglerade krav som definierar ett idealiskt rostskydd. Om beställaren för varje objekt inventerar behoven i entreprenaden och beslutar om en prioriteringsordning av funktionsmålen, kan rangordningen användas för att ta fram objektspecifika funktionskrav. För att stimulera till nytänkande och användning av alternativa produkter och processlösningar skulle det vara fördelaktigt att tillåta sidoanbud i upphandlingar med funktionskrav. Entreprenörerna skulle till exempel kunna lämna ett huvudanbud som ska följa den generella kravställningen med utförandekrav enligt SIS-TS 44, och ett kompletterande sidoanbud som adresserar de objektspecifika funktionskraven och funktionsmålen. Sidoanbuden kan utvärderas med livscykelanalyser, typprovning och inspektion av referensobjekt. Inom projektet har arbetsgruppen tagit fram en LCA-analys och en LCC analys för dagens målningsprogram så som det beskrivs i SIS-TS 44. Inom projektet har den gällande kravställningen i SIS-TS 44 granskats med utgångspunkt att revidera de krav som kan komma att stå i vägen för tillämpningen av nya alternativa produkter och metoder med förbättrade egenskaper. Avsnitt 9 i rapporten innehåller en sammanfattad handlingsplan för hur en funktionsbaserad kravställning skulle kunna användas för att introducera nya produkter och metoder i Trafikverkets krav för rostskyddsmålning.BBT Förändring av kravställning för rostskyddsmålning av stålkonstruktione

Basic concepts and applications of functional magnetic resonance imaging for radiotherapy of prostate cancer

Recently, the interest to integrate magnetic resonance imaging (MRI) in radiotherapy for prostate cancer has increased considerably. MRI can contribute in all steps of the radiotherapy workflow from diagnosis, staging, and target definition to treatment follow-up. Of particular interest is the ability of MRI to provide a wide range of functional measures. The complexity of MRI as an imaging modality combined with the growing interest of the application to prostate cancer radiotherapy, emphasize the need for dedicated education within the radiation oncology community. In this context, an overview of the most common as well as a few upcoming functional MR imaging techniques is presented: the basic methodology and measurement is described, the link between the functional measures and the underlying biology is established, and finally relevant applications of functional MRI useful for prostate cancer radiotherapy are given

Influence of heat treatment on lipid oxidation and glutathione peroxidase activity in chicken and duck meat

To study the role of glutathione peroxidase for lipid oxidation in meat, chicken and duck muscle were heated to an internal temperature of 60, 70 or 80 degrees C and the meats were then stored at 8 degrees C for up to 6 days. Thiobarbituric-acid-reactive substances (TBARS) and glutathione peroxidase (GSHPx) activity were measured on days 0, 1, 3 and 6. In heated muscle samples, TBARS increased during 6 days of storage. GSHPx activity was diminished with increasing temperature and was much more affected by the internal temperature than by the length of the subsequent cold storage, whereas the formation of TBARS was affected by both the final temperature and storage time. Meat samples, which had been heated to 80 degrees C, were also used to investigate the effect of added GSHPx on lipid oxidation. GSHPx (2 or 4 U) was added per I g meat after cooking, and the concentration of TBARS and GSHPx activity were measured on day 0 and 6. Chicken muscle samples with added GSHPx had a lower TBARS concentration on day 6 (2 U/g meat: 58% and 4 U/g meat: 54%) compared to the control without added GSHPx. In contrast, GSHPx addition had no effect on lipid oxidation in heated duck muscle. The study shows that there was a reciprocal relationship between TBARS formation and GSHPx activity and that addition of GSHPx could decrease lipid oxidation. (c) 2006 Elsevier Ltd. All rights reserved

Regional recurrence of oropharyngeal cancer after definitive radiotherapy : a case control study

Background: Elective treatment of lymph nodes in oropharyngeal cancer (OPC) has impact on both regional recurrences (RR) and risk of late side effects. This study was performed to quantify the dose-dependent impact on RR and overall survival (OS) in a prospectively collected cohort of OPC from the ARTSCAN study with emphasis on elective treatment. Methods: ARTSCAN is a previously published prospective, randomized, multicentre study of altered radiotherapy (RT) fractionation in head and neck cancer. In ARTSCAN the elective treatment volume for node positive OPC varied significantly between centres due to local treatment principles. All patients with OPC in complete response after primary treatment were eligible for the present case-control study. Cases were patients with RR during five years follow-up. Patients with no recurrence were eligible as controls. Four controls per case were matched according to T-and N-stage. Mean (D-mean) and median (D-50%) dose for the lymph node level (LNL) of RR in the cases and the corresponding LNL in the controls were analysed with conditional logistic regression. OS was estimated with the Kaplan-Meier method and evaluated by multivariate Cox regression analysis. Results: There was a dose-dependent risk reduction for D-50% in the interval that represented elective treatment (40-50 Gy) (OR = 0.18, p < 0.05) and a trend in the same dose interval for D-mean (OR = 0.19, p = 0.07). OS rates at five years were 0.39 (0.24-0.65) for cases and 0.70 (0.62-0.81) for controls (p < 0.001). The Kaplan-Meier and the Cox regression analysis for cases categorised by delivered dose showed an inverse relationship between dose and survival. The cases with RR in a LNL outside planning target volume (PTV) (D-mean < 40 Gy) had an OS rate comparable to that of all patients, and those with RR in a LNL in PTVelective (D-mean 40-60 Gy) or PTVtumour (D-mean > 60 Gy) did significantly worse (p < 0.05). The same inverse relationship was also shown for a small subset of patient with known HPV-status, defined by over expression of p16 (p < 0.05). Conclusions: There was a significant risk reduction for RR of elective treatment. However the OS for patients with RR outside target volumes was not affected, with similar results for patients with HPV-positive OPC. This could be an argument for a prospective randomized study on limited elective target volumes in OPC