| 1. |
- Sandström, Monica, 1946-, et al.
(author)
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External power frequency magnetic field-induced jitter on computer monitors
- 1993
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In: Behaviour & Information Technology. - : Taylor & Francis. - 0144-929X .- 1362-3001. ; 12:6, s. 359-363
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Journal article (peer-reviewed)abstract
- Power frequency magnetic fields with flux densities greater than 0.5 μT are not uncommon in offices. This level has been shown to induce jitter on VDT monitors. In the present project, these magnetic field-induced disturbances have been studied in the laboratory in order to establish a firm technical basis for future studies of the disturbance's influence on eye strain in VDT workers. Eight volunteers judged the occurrence of distortion when an applied external magnetic field was varied both in amplitude and frequency for 8 investigated VDT screens. The level of the external 50 Hz magnetic field when the distortion was detectable ranged from 0.6 to 1.1 μT. If the screen was viewed through a stereomicroscope (25 × magnification), the corresponding level was in the order of 0.2 μT. If the frequency difference between the external magnetic field and the refresh rate of the screen is only ±1-2 Hz, the disturbance is noticeable at even lower flux densities.
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| 2. |
- Andersson, N., et al.
(author)
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Amplitude modulation of light from various sources
- 1994
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In: Lighting Research and Technology. - : Sage Publications. - 1477-1535 .- 1477-0938. ; 26:3, s. 157-160
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Journal article (peer-reviewed)abstract
- This work was done to obtain basic knowledge about various light sources and specially about light modulation, or flicker. The study showed that the modulation of light varied a lot between different ordinary light sources. In general the 100 Hz component in the flickering light dominated. For incandescent lights the modulation increased with decreasing power and was in the range 10-22%. Light from the tungsten-halogen lamps had 2-6% modulation. The most common light sources (single-colour fluorescent light) had a modulation of about 20%. Fluorescent tubes with better colour rendering (full-colour fluorescent and full-colour special fluorescent tubes) had a higher modulation, 30-40%, while light from high-frequency (HF) fluorescent tubes had a modulation of 0.9%. Light from conventional compact fluorescent tubes had a modulation degree of about 44%, and for HF compact fluorescent tubes it was 2-7%. Modulation of light from HF compact fluorescent tubes had a tendency to decrease with increasing tube size. The modulation of light from discharge lamps was in the range of 52% up to 100% and the curve form of the light from low pressure sodium vapour lamp (100% modulation) contained several high frequency components.
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| 3. |
- de Ståhl, Teresita Diaz, et al.
(author)
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The Swedish childhood tumor biobank : systematic collection and molecular characterization of all pediatric CNS and other solid tumors in Sweden
- 2023
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In: Journal of Translational Medicine. - : BioMed Central (BMC). - 1479-5876. ; 21
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Journal article (peer-reviewed)abstract
- The Swedish Childhood Tumor Biobank (BTB) is a nonprofit national infrastructure for collecting tissue samples and genomic data from pediatric patients diagnosed with central nervous system (CNS) and other solid tumors. The BTB is built on a multidisciplinary network established to provide the scientific community with standardized biospecimens and genomic data, thereby improving knowledge of the biology, treatment and outcome of childhood tumors. As of 2022, over 1100 fresh-frozen tumor samples are available for researchers. We present the workflow of the BTB from sample collection and processing to the generation of genomic data and services offered. To determine the research and clinical utility of the data, we performed bioinformatics analyses on next-generation sequencing (NGS) data obtained from a subset of 82 brain tumors and patient blood-derived DNA combined with methylation profiling to enhance the diagnostic accuracy and identified germline and somatic alterations with potential biological or clinical significance. The BTB procedures for collection, processing, sequencing, and bioinformatics deliver high-quality data. We observed that the findings could impact patient management by confirming or clarifying the diagnosis in 79 of the 82 tumors and detecting known or likely driver mutations in 68 of 79 patients. In addition to revealing known mutations in a broad spectrum of genes implicated in pediatric cancer, we discovered numerous alterations that may represent novel driver events and specific tumor entities. In summary, these examples reveal the power of NGS to identify a wide number of actionable gene alterations. Making the power of NGS available in healthcare is a challenging task requiring the integration of the work of clinical specialists and cancer biologists; this approach requires a dedicated infrastructure, as exemplified here by the BTB.
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| 4. |
- Hansson Mild, Kjell, et al.
(author)
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Exposure of workers to electromagnetic fields. A review of open questions on exposure assessment techniques
- 2009
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In: International Journal of Occupational Safety and Ergonomics. - Warszawa : Central Institute for Labour Protection. - 1080-3548 .- 2376-9130. ; 15:1, s. 3-33
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Journal article (peer-reviewed)abstract
- European Directive 2004/40/EC on occupational exposure to electromagnetic fields (EMF), based on the guidelines of the International Commission on Non-Ionizing Radiation Protection, was to be implemented in the Member States of the European Union by 2008. Because of some unexpected problems the deadline was postponed until 2012. This paper reviews some of the problems identified and presents some suggestions for possible solutions based on the authors' experience in assessing occupational exposure to EMF. Among the topics discussed are movement in static magnetic fields, ways to time average extreme low frequency signals, the difference between emission and exposure standards, and ways of dealing with those issues.
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| 5. |
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| 6. |
- Johansson, Amanda, et al.
(author)
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No effect of mobile phone-like RF exposure on patients with atopic dermatitis
- 2008
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In: Bioelectromagnetics. - : Wiley. - 0197-8462 .- 1521-186X. ; 29:5, s. 353-362
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Journal article (peer-reviewed)abstract
- This study investigates the effect of exposure to a mobile phone-like radiofrequency (RF) electromagnetic field on people with atopic dermatitis (AD). Fifteen subjects with AD were recruited and matched with 15 controls without AD. The subjects were exposed for 30 min to an RF field at 1 W/kg via an indoor base station antenna attached to a 900 MHz GSM mobile phone. Blood samples for ELISA analysis of the concentration of substance P (SP), tumor necrosis factor receptor 1 (TNF RI), and brain derived neurotrophic factor (BDNF) in serum were drawn before and after the provocation (exposure/sham). Baseline heart rate and heart rate variability, local blood flow, and electrodermal activity were also recorded. No significant differences between the subject groups were found for baseline neurophysiological data. The cases displayed a serum concentration of TNF RI significantly higher than the control subjects and a significantly lower serum concentration of BDNF in the baseline condition. For SP there was no difference between groups. However, no effects related to RF exposure condition were encountered for any of the measured substances. As to symptoms, a possible correlation with exposure could not be evaluated, due to too few symptom reports. The result of the study does not support the hypothesis of an effect of mobile phone-like RF exposure on serum levels of SP, TNF RI, and BDNF in persons with AD.
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| 7. |
- Johansson, Amanda, et al.
(author)
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Symptoms, personality traits, and stress in people with mobile phone-related symptoms and electromagnetic hypersensitivity
- 2010
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In: Journal of Psychosomatic Research. - : Elsevier. - 0022-3999 .- 1879-1360. ; 68:1, s. 37-45
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Journal article (peer-reviewed)abstract
- Some people report symptoms that they associate with electromagnetic field (EMF) exposure. These symptoms may be related to specific EMF sources or to electrical equipment in general (perceived electromagnetic hypersensitivity, EHS). Research and clinical observations suggest a difference between mobile phone (MP)-related symptoms and EHS with respect to symptom prevalence, psychological factors, and health prognosis. This study assessed prevalence of EMF-related and EMF-nonrelated symptoms, anxiety, depression, somatization, exhaustion, and stress in people with MP-related symptoms or EHS versus a population-based sample and a control sample without EMF-related symptoms.
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| 8. |
- Lundström, Marita, 1955-
(author)
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Förskolebarns strävanden att kommunicera matematik
- 2015
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Doctoral thesis (other academic/artistic)abstract
- The aim of this study is to explore and describe preschool children’s use of mathematics in their communication with others. This study is limited to examining situations in which children communicate with other children and adults. Moreover, the aim is to deepen the understanding of how preschool children use mathematics to convey mathematical meanings with other children and adults in preschool. The research questions is: How do children communicate mathematics? In what kind of situations does mathematics occur in their communication? What mathematical content is communicated? The theoretical framework is selected from a sociocultural perspective, which is a collective term for theories which assume that language's original function is communicative and that it is a means of social interaction. From a socio-cultural perspective, language, culture and children's actions are seen as essential elements of childhood development and learning. Prerequisites for this development include children’s participation in creating an interaction with their environment. In order to study preschool children's mathematical communication, this study is based in ethnographic methodological traditions. The results show that preschool children communicate mathematics through: linguistic expressions, semiotics, linguistic tools and bodily expressions. Children communicate mathematically in situations when: they are making comparisons, when they are comparing changes, and when they are trying to give descriptions about the world which surrounds them. It also shows that preschool routines, material support and activities stimulate mathematical communication. When teachers are supportive and engaged in children’s communication their mathematical knowledge can also be developed and deepened
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