| 1. |
|
|
| 2. |
- Ambatipudi, Radhika, 1982-
(författare)
-
High Frequency (MHz) Planar Transformers for Next Generation Switch Mode Power Supplies
- 2013
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Increasing the power density of power electronic converters while reducing or maintaining the same cost, offers a higher potential to meet the current trend inrelation to various power electronic applications. High power density converters can be achieved by increasing the switching frequency, due to which the bulkiest parts, such as transformer, inductors and the capacitor's size in the convertercircuit can be drastically reduced. In this regard, highly integrated planar magnetics are considered as an effective approach compared to the conventional wire wound transformers in modern switch mode power supplies (SMPS). However, as the operating frequency of the transformers increase from several hundred kHz to MHz, numerous problems arise such as skin and proximity effects due to the induced eddy currents in the windings, leakage inductance and unbalanced magnetic flux distribution. In addition to this, the core losses whichare functional dependent on frequency gets elevated as the operating frequency increases. Therefore, this thesis provides an insight towards the problems related to the high frequency magnetics and proposes a solution with regards to different aspects in relation to designing high power density, energy efficient transformers.The first part of the thesis concentrates on the investigation of high power density and highly energy efficient coreless printed circuit board (PCB) step-down transformers useful for stringent height DC-DC converter applications, where the core losses are being completely eliminated. These transformers also maintain the advantages offered by existing core based transformers such as, high coupling coefficient, sufficient input impedance, high energy efficiency and wide frequencyband width with the assistance of a resonant technique. In this regard, several coreless PCB step down transformers of different turn’s ratio for power transfer applications have been designed and evaluated. The designed multilayered coreless PCB transformers for telecom and PoE applications of 8,15 and 30W show that the volume reduction of approximately 40 - 90% is possible when compared to its existing core based counterparts while maintaining the energy efficiency of the transformers in the range of 90 - 97%. The estimation of EMI emissions from the designed transformers for the given power transfer application proves that the amount of radiated EMI from a multilayered transformer is lessthan that of the two layered transformer because of the decreased radius for thesame amount of inductance.The design guidelines for the multilayered coreless PCB step-down transformer for the given power transfer application has been proposed. The designed transformer of 10mm radius has been characterized up to the power level of 50Wand possesses a record power density of 107W/cm3 with a peak energy efficiency of 96%. In addition to this, the design guidelines of the signal transformer fordriving the high side MOSFET in double ended converter topologies have been proposed. The measured power consumption of the high side gate drive circuitvitogether with the designed signal transformer is 0.37W. Both these signal andpower transformers have been successfully implemented in a resonant converter topology in the switching frequency range of 2.4 – 2.75MHz for the maximum load power of 34.5W resulting in the peak energy efficiency of converter as 86.5%.This thesis also investigates the indirect effect of the dielectric laminate on the magnetic field intensity and current density distribution in the planar power transformers with the assistance of finite element analysis (FEA). The significanceof the high frequency dielectric laminate compared to FR-4 laminate in terms of energy efficiency of planar power transformers in MHz frequency region is also explored.The investigations were also conducted on different winding strategies such as conventional solid winding and the parallel winding strategies, which play an important role in the design and development of a high frequency transformer and suggested a better choice in the case of transformers operating in the MHz frequency region.In the second part of the thesis, a novel planar power transformer with hybrid core structure has been designed and evaluated in the MHz frequency region. The design guidelines of the energy efficient high frequency planar power transformerfor the given power transfer application have been proposed. The designed corebased planar transformer has been characterized up to the power level of 50W and possess a power density of 47W/cm3 with maximum energy efficiency of 97%. This transformer has been evaluated successfully in the resonant converter topology within the switching frequency range of 3 – 4.5MHz. The peak energy efficiency ofthe converter is reported to be 92% and the converter has been tested for the maximum power level of 45W, which is suitable for consumer applications such as laptop adapters. In addition to this, a record power density transformer has been designed with a custom made pot core and has been characterized in thefrequency range of 1 - 10MHz. The power density of this custom core transformer operating at 6.78MHz frequency is 67W/cm3 and with the peak energy efficiency of 98%.In conclusion, the research in this dissertation proposed a solution for obtaining high power density converters by designing the highly integrated, high frequency(1 - 10MHz) coreless and core based planar magnetics with energy efficiencies inthe range of 92 - 97%. This solution together with the latest semiconductor GaN/SiC switching devices provides an excellent choice to meet the requirements of the next generation ultra flat low profile switch mode power supplies (SMPS).
|
|
| 3. |
- Andersson, Henrik, et al.
(författare)
-
Processing and Characterization of a MOS Type Tetra Lateral Position Sensitive Detector with Indium Tin Oxide Gate Contact
- 2008
-
Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 8:9-10, s. 1704-1709
-
Tidskriftsartikel (refereegranskat)abstract
- A 2-D tetra lateral position sensitive detector (PSD) based on the metal-oxide-semiconductor (MOS) principle has been manufactured and characterized. The active area of the device is 5 nun x 5 mm and the intention is to use the central 4 nun x 4 nun for low nonlinearity measurements. The gate contact is made of indium tin oxide (ITO) that is a degenerate electrically conducting semiconductor, which, in addition, is also transparent in the visible part of the spectrum. The use of a MOS structure results in a processing with no necessity to use implantation or diffusion in order to make the resistive p-layer as in a conventional p-n junction lateral effect PSD. Position measurements show good linearity in the middle 4 nun x 4 mm area. Within the middle 2.1 mm x 2.1 mm, the nonlinearity is within 1.7% of the active area with a position detection error of maximum 60 mu m. Measured MOS IV characteristics are compared to a level 3 spice model fit and show good agreement. The threshold voltage is determined to be -0.03 V. Responsivity measurements show a high sensitivity in the visible spectral region.
|
|
| 4. |
- Ascher, Henry, 1953, et al.
(författare)
-
Stöd till ensamkommande barn och unga – effekter, erfarenheter och upplevelser
- 2018
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Begreppet ensamkommande barn innefattar enligt svensk lag asylsökande barn under 18 år som vid ankomsten till mottagarlandet är skilda från såväl föräldrar som annan vuxen person som kan anses ha trätt in i föräldrarnas ställe, eller barn som efter ankomsten står utan sådan ställföreträdare. Vår systematiska genomgång av den vetenskapliga litteraturen har inte funnit några kontrollerade studier som har undersökt eller jämfört effekter av olika stödjande insatser för ensamkommande barn och unga. Vår systematiska genomgång av forskning som på olika sätt belyser ensamkommande barns och ungas erfarenheter och upplevelser av vad som främjar och hämmar deras sociala integrering, psykiska och fysiska hälsa och funktionsförmåga, har resulterat i sju övergripande teman (teman på nivå tre*): – Säkerhet och kontroll: En grundläggande förutsättning. Ensamkommande barns och ungas erfarenheter av trauma och förlust, i kombination med osäkerhet om framtiden, innebär en brist på grundläggande trygghet, kontroll och säkerhet. Det präglar starkt tillvaron och påverkar välbefinnandet och förmågan att hantera sin vardag och sina svårigheter samt att kunna se en framtid. – Det nya landet: Både möjligheter och svårigheter. Ensamkommande barn och unga uttrycker en stark motivation att utbilda sig, att anpassa sig till det nya landet och att ta vara på de möjligheter som finns. Samtidigt beskrivs strukturella och sociala hinder samt svårigheter kopplade till att befinna sig i en ny kulturell och samhällelig kontext. Allt detta kan hämma en positiv utveckling av hälsa, integration och funktionsförmåga. – Att hantera svårigheter: En balans mellan olika strategier. Copingstrategier (strategier för att med tankar och beteenden hantera svårigheter) såsom undvikande, flykt och positivt tänkande, kan fungera främjande men ibland också hindrande för hälsa, integration och funktionsförmåga. Religion kan upplevas som betydelsefull för välmående och förmåga att hantera svårigheter. – Vardagsmiljöer: Stödjande relationer, inflytande i boende och tillgång till skola och aktiviteter är viktigt. Ensamkommande barn och unga framhåller stöd, goda relationer och eget inflytande i boendet samt måltider i boendet som viktiga, oberoende av boendeform. Skolan upplevs som viktig för inlärning, välmående och relationer. Betydelsen av stöd och råd från vuxna i skola och i förhållande till skola och utbildning understryks. När det gäller skolan som plats för att utveckla relationer med jämnåriga beskrivs både positiva och negativa erfarenheter. Fritidsaktiviteter beskrivs som viktiga för att må bra, för att bygga sociala relationer och återskapa mening i tillvaron. – Relationer: Stöd och vägledning från vuxna är betydelsefullt, kontakt med jämnåriga viktigt men också svårt. Ensamkommande barn och unga lyfter betydelsen av vägledning, stöd, kontinuitet men också möjligheter till inflytande och självständighet i relation till vuxna. Relationer till jämnåriga upplevs som viktigt men också svårt. Relationer till biologisk familj innebär både saknad och stöd. Beroende på kvaliteten i de olika relationerna kan de fungera hämmande eller främjande för välbefinnande och utveckling. – Socialtjänst och hälso- och sjukvård: Varierande uppfattningar om och erfarenheter av stöd och behov. Ensamkommande barn och unga upplever socialtjänsten som viktig för grundläggande stöd, men också att stödet inte är tillräckligt. De uttrycker varierande uppfattningar om och erfarenheter av psykologiskt stöd från hälso- och sjukvården. – Identitet och tillhörighet: Att få ihop det förflutna, nuet och framtiden. Ensamkommande barn och unga strävar efter att både bevara modersmål och kultur och att anpassa sig till det nya landet samt att bevara relationer till personer i ursprungslandet och att stödja dem. De kan kämpa med att få ihop sin tillhörighet. Religion kan vara ett sätt att skapa en kontinuitet i tillvaron. * Teman på nivå tre är formulerade så att de centrala budskapen ska framgå. De har använts för att ordna och presentera resultatet på ett enkelt och läsvänligt sätt. Temana har kondenserats utifrån samtliga andra nivåns teman, oavsett evidensstyrka.
|
|
| 5. |
- Axelsson, Mette, et al.
(författare)
-
Mat vid diabetes. : En systematisk översikt med utvärdering av effekter samt hälsoekonomiska och etiska aspekter.
- 2022
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- SlutsatserTyp 1- och typ 2-diabetes Det finns ett samband mellan att äta medelhavskost och lägre risk att dö i förtid oavsett orsak (måttlig tillförlitlighet). Det finns ett samband mellan att äta en större andel2 fibrer eller baljväxter och lägre risk att dö i förtid oavsett orsak (måttlig tillförlitlighet). Det kan även finnas ett samband mellan att äta en större andel nötter och lägre risk att dö i förtid oavsett orsak (låg tillförlitlighet) samt lägre risk att insjukna i hjärt- och kärlsjukdom (låg tillförlitlighet). Det finns ett samband mellan att dricka mer2 kaffe och lägre risk att dö i förtid oavsett orsak och lägre risk att dö i förtid i kranskärlssjukdom (måttlig tillförlitlighet) samt möjligen en lägre risk att dö i förtid i hjärt- och kärlsjukdom (låg tillförlitlighet). Det råder generell brist på studier med lång uppföljningstid som jämför inverkan av olika slags kostråd på överlevnad, diabeteskomplikationer, diabetesremission3, livskvalitet och biverkningar. Tillförlitligheten av befintliga resultat är dessutom mycket låg för de flesta koster, kostbehandlingar, livsmedel och näringsämnen som har utvärderats. Effekter på hälsa och relaterade mått kan i dessa fall inte bedömas.2. Begreppet ”större andel” eller ”mer” avser inte nödvändigtvis att äta eller dricka mer totalt utan att öka mängden av ett visst livsmedel genom att byta ut annan mat eller dryck.Typ 2-diabetes Det kan finnas ett samband mellan att äta en större andel mättat fett och högre risk för att dö i förtid av hjärt- och kärlsjukdom (låg tillförlitlighet). Det kan även finnas ett samband mellan att äta en större andel enkelomättat fett och lägre risk att dö i förtid oavsett orsak (låg tillförlitlighet). En behandling med en initial period av kraftigt minskat energiintag med hjälp av lågenergipulver (VLED) med efterföljande övergång till mat för viktstabilitet jämfört med vanlig kostbehandling har gynnsamma effekter på livskvalitet (enligt EQ-5D), långtidsblodsocker (HbA1c) och vikt upp till 12 månader (måttlig tillförlitlighet)4. Vidare kan metoder där VLED ingår ha gynnsamma effekter på diabetesremission5 och midjeomfång upp till 12 månader (låg tillförlitlighet) och långtidsblodsocker (HbA1c) upp till 24 månader (låg tillförlitlighet). Intensiv livsstilsbehandling därlågfettkost kombineras med fysisk aktivitet och minskat energiintag har gynnsamma effekter jämfört med vanlig kostbehandling på långtidsblodsocker (HbA1c), vikt, kroppsmasseindex (BMI), midjeomfång och vissa blodfetter upp till 12 månader (måttlig tillförlitlighet)3. Viktminskningen kan kvarstå upp till omkring 10 år (låg tillförlitlighet). Behandlingen kan leda till bättre fysisk livskvalitet upp till 8 år (låg tillförlitlighet) medan effektskillnaden i psykisk livskvalitet under samma tid kan vara obefintlig eller försumbar (låg tillförlitlighet). Jämförelsen påvisar ingen förändrad risk att dö i förtid oavsett orsak eller att dö eller insjukna av kardiovaskulära orsaker efter omkring 10 år (låg tillförlitlighet). I det hälsoekonomiska perspektivet är intensiv livsstilsbehandling mer resurskrävande än vanlig kostbehandling, och beräkningar visar små eller inga vinster i kvalitetsjusterade levnadsår (QALYs) på individnivå. Energirestriktion i samband med intensiv livsstilsbehandling med ketogen kost eller med högproteinkost (20 E%) i kombination med fysisk aktivitet jämfört med vanlig kostbehandling kan ge en viktminskning upp till 11 månader (låg tillförlitlighet) men det saknas studier som kan visa om vikten kan bibehållas på längre sikt. Det saknas studier som undersökt kliniskt viktiga utfall som dödlighet, kardiovaskulära sjukdomar, livskvalitet och diabetesremission.3. Gäller endast vid typ 2-diabetes.4. Utgår från individer med en medelkroppsvikt på cirka 100 kg och medel-HbA1c på 60 mmol/mol.5. Resultaten för utfallet diabetesremission (att uppnå normala blodsockervärden) gäller när en diabetesdiagnos sattes för mindre än 6 år sedan eller för mindre än 3 år sedan. Definitionen för diabetesremission var ett HbA1c på mindre än 48 mmol/mol och att samtidigt vara fri från blodsockersänkande läkemedel.Graviditetsdiabetes Det saknas studier om kost vid graviditetsdiabetes med tillräcklig tillförlitlighet för att kunna bedöma effekterna.
|
|
| 6. |
- Bertilsson, Göran
(författare)
-
Studies on nuclear receptors involved in drug metabolism
- 2001
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The molecular basis for drug metabolism is starting to emerge as a result of cloning and characterization of a group of nuclear receptors that respond to drugs by transcriptional regulation of key genes encoding enzymes involved in metabolism of commonly used drugs. This thesis describes the identification and functional, as well as the structural, characterization of one of these receptors, the human pregnenolone activated receptor (hPAR, NR1I2) that also has been referred to as the pregnane X receptor (PXR) or the steroid and xenobiotic receptor (SXR) by others. Functional characterization of this, and the closely related, constitutively active receptor CAR (NR1I3) has shown that both PXR and CAR are important for cytochrome P450 gene induction and thus are likely to be important mediators of drug metabolism. PXR was identified by homology searching of human EST databases and two differentially spliced mRNAs were cloned. The expression was high in liver and intestine, and PXR was activated by a large and chemically diverse group of compounds including drugs metabolized by CYP3A4. A transient transfection study using an expression plasmid for PXR together with a luciferase reporter construct, containing a part of the CYP3A4 promoter (- 176 to - 146), showed that PXR induced the expression of this reporter. Based on this study we suggested that PXR was a novel sensor for sterol and xenobiotic metabolism. To further investigate the regulatory role of PXR in CYP3A induction we cloned approximately 10 kb of both the CYP3A7 and the CYP3A4 gene promoters. These two promoters exhibited 90 % sequence identity up to -8,8 kb, indicating a close evolutionary distance between the two genes. A combination of promoter deletion analyses and transient transfections suggests that PYCR and CAR are important for CYP3A4 and CYP3A7 gene induction through a functionally conserved distally located xenobiotic responsive enhancer module. Taken together, we propose that PXR and CAR play important roles in xenobiotic regulation, not only for CYP3A4 regulation in adults, but also for CYP3A7 to protect the embryo against endogenous and exogenous toxins. The chemically broad activation profile of PXR suggested that this receptor could be structurally related to the PPARs (NR1C1-3), another subgroup of orphan nuclear receptors with promiscuous ligand binding proper-ties. We found from the crystal structure of the PPAR gamma ligand binding domain that this receptor has a larger and more accessible ligand binding pocket than other nuclear receptors binding to a structurally more limited set of ligands. We also made a model of the ligand binding domain of PXR based on the available co-crystal structure of VDR (NR1I1), and 1alpha 25-dihydroxyvitamin D3. The model indicated important residues of the ligand binding pocket of PXR. We mutated polar residues from human to mouse and tested them in transient transfection in combination with species specific compounds. The results have increased our understanding for species specific ligand binding to PXR. In addition, we also made a single point mutation in PYR that yielded a constitutive active form of the receptor. PPARgamma agonists belonging to the thiazolidinedione (TZD) class of compounds are currently used for treatment of diabetes type 2. Troglitazone, a TZD, is known to induce CYP3A4 activity. The TZI)s troglitazone, pioglitazone and rosiglitazone were all found to activate PXR on a CYP3A4 promoter. Furthermore an insulin sensitizing non-TZD ligand, JTT-501, did not activate the nuclear receptor PXR but dually activated PPAR alpha and gamma. Therefore JTT is less likely to mediate drug- interactions due to PXR mediated CYP3A4 induction. In conclusion, screening against PXR activation is predicted to be a valuable tool in pre-clinical drug development to obtain better and safer drugs.
|
|
| 7. |
- Bertilsson, Kent, et al.
(författare)
-
Simulation of a low atmospheric-noise modified four-quadrant position sensitive detector
- 2001
-
Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - 0168-9002 .- 1872-9576. ; 466:1, s. 183-187
-
Tidskriftsartikel (refereegranskat)abstract
- A modified four-quadrant position sensitive detector (PSD) is developed. This structure is less sensitive to atmospheric turbulence that is a major drawback with the traditional four-quadrant detector. The inter-electrode resistance is as high as for the four-quadrant detector, which is an advantage compared to the lateral effect PSD. The linearity for the modified four-quadrant detector is good in the whole active range of sensing. The structures are limited to small sensing areas with well focused beams and are suitable for use in detectors up to 1 mm in size.
|
|
| 8. |
- Blomqvist, Göran, 1963-, et al.
(författare)
-
Magnetiserbarhet – avgränsning och tillståndskartering för askkonstruktioner : Utvärdering av magnetiserbarhet som metod för att kontrollera askkonstruktioners tillstånd och avgränsning
- 2012
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Vägar och andra anläggningar byggda med askor erbjuder miljöfördelar i form av resurssnålare och i vissa fall effektivare konstruktioner än konventionella material. Men, förekomsten av miljöstörande ämnen i askor ger även upphov till risker om de kommer i kontakt med omgivningen. Projektet syftar till att undersöka om magnetiserbarhet kan användas för att bedöma askkonstruktioners tillstånd och avgränsning. Hypotesen är att askorna har en högre magnetiserbarhet än de material som täcker dem och att man genom att mäta magnetiserbarheten i en volym som innefattar såväl det överliggande materialet som askan, kan bedöma tillståndet (tjockleken eller uppblandningsgraden) hos materialen. Därför har ett 20-tal olika material slaggruser, flygaskor, grusslitlager och jordarter undersökts samt två fältlokaler karterats. Projektet är ett samarbete mellan VTI och SGI.
|
|
| 9. |
- Capo, Eric, et al.
(författare)
-
Lake sedimentary dna research on past terrestrial and aquatic biodiversity: Overview and recommendations
- 2021
-
Ingår i: Quaternary. - : MDPI. - 2571-550X. ; 4:1
-
Forskningsöversikt (refereegranskat)abstract
- The use of lake sedimentary DNA to track the long-term changes in both terrestrial and aquatic biota is a rapidly advancing field in paleoecological research. Although largely applied nowadays, knowledge gaps remain in this field and there is therefore still research to be conducted to ensure the reliability of the sedimentary DNA signal. Building on the most recent literature and seven original case studies, we synthesize the state-of-the-art analytical procedures for effective sampling, extraction, amplification, quantification and/or generation of DNA inventories from sedimentary ancient DNA (sedaDNA) via high-throughput sequencing technologies. We provide recommendations based on current knowledge and best practises.
|
|
| 10. |
|
|
| 11. |
- Helgesson, Gert, et al.
(författare)
-
Ethical aspects of diagnosis and interventions for children with fetal alcohol Spectrum disorder (FASD) and their families
- 2018
-
Ingår i: BMC Medical Ethics. - : BIOMED CENTRAL LTD. - 1472-6939. ; 19
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Fetal alcohol spectrum disorders (FASD) is an umbrella term covering several conditions for which alcohol consumption during pregnancy is taken to play a causal role. The benefit of individuals being identified with a condition within FASD remains controversial. The objective of the present study was to identify ethical aspects and consequences of diagnostics, interventions, and family support in relation to FASD.Methods: Ethical aspects relating to diagnostics, interventions, and family support regarding FASD were compiled and discussed, drawing on a series of discussions with experts in the field, published literature, and medical ethicists.Results: Several advantages and disadvantages in regards of obtaining a diagnosis or description of the condition were identified. For instance, it provides an explanation and potential preparedness for not yet encountered difficulties, which may play an essential role in acquiring much needed help and support from health care, school, and the socia ! services. There are no interventions specifically evaluated for FASD conditions, but training programs and family support for conditions with symptoms overlapping with FASD, e.g. ADHD, autism, and intellectual disability, are likely to be relevant. Stigmatization, blame, and guilt are potential downsides. There might also be unfortunate prioritization if individuals with equal needs are treated differently depending on whether or not they meet the criteria for a specific condition. Conclusions: The value for the concerned individuals of obtaining a FASD-related description of their condition - for instance, in terms of wellbeing - is not established. Nor is it established that allocating resources based, on whether individuals fulfil FASD-related criteria is justified, compared to allocations directed to the most prominent specific needs.
|
|
| 12. |
- Hellberg, Christel, et al.
(författare)
-
Evidence and evidence gaps in assessments and interventions in areas related to social work research and practice – an overview of four evidence maps : [Vetenskapligt kunskapsläge om utredning och insatser i socialt arbete och forskning –en sammanställning av fyra kartläggningar]
- 2023
-
Ingår i: European Journal of Social Work. - : Informa UK Limited. - 1369-1457 .- 1468-2664. ; 26:5, s. 882-895
-
Tidskriftsartikel (refereegranskat)abstract
- This overview of four evidence maps is based on systematic reviews of assessment and interventions in social work practice. The aim was to investigate the evidence and evidence gaps within four important areas for social work research and practice. Descriptive data on search strategies and domains were collected from four evidence maps, on Social Assistance, Substance Dependence, Care for older adults respectively for persons with disabilities. The scientific quality and scientific evidence were assessed. Key findings were summarised by analyzing and discussing common and specific elements in the evidence maps. The overview was undertaken in close collaboration between researchers with expertise in the field and a government agency. The overview identified both evidence and evidence gaps with respect to effects and experiences of interventions and assessment methods in four evidence maps. Evidence maps provide a comprehensive picture of the state of social services research and can thereby be of use to both researchers and practitioners, and in the production of evidence based social work.
|
|
| 13. |
- Intarasiri, S., et al.
(författare)
-
Crystalline quality of 3C-SiC formed by high-fluence C+-implanted Si
- 2007
-
Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 253:11, s. 4836-4842
-
Tidskriftsartikel (refereegranskat)abstract
- Carbon ions at 40 keV were implanted into (1 0 0) high-purity p-type silicon wafers at 400 degrees C to a fluence of 6.5 x 10(17) ions/cm(2). Subsequent thermal annealing of the implanted samples was performed in a diffusion furnace at atmospheric pressure with inert nitrogen ambient at 1100 degrees C. Time-of-flight energy elastic recoil detection analysis (ToF-E ERDA) was used to investigate depth distributions of the implanted ions. Infrared transmittance (IR) and Raman scattering measurements were used to characterize the formation of SiC in the implanted Si substrate. X-ray diffraction analysis (XRD) was used to characterize the crystalline quality in the surface layer of the sample. The formation of 3C-SiC and its crystalline structure obtained from the above mentioned techniques was finally confirmed by transmission electron microscopy (TEM). The results show that 3C-SiC is directly formed during implantation, and that the subsequent high-temperature annealing enhances the quality of the polycrystalline SiC.
|
|
| 14. |
- Jonsson, Ulf, et al.
(författare)
-
Psychological Treatment of Depression in People Aged 65 Years and Over : A Systematic Review of Efficacy, Safety, and Cost-Effectiveness.
- 2016
-
Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 11:8
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Depression in elderly people is a major public health concern. As response to antidepressants is often unsatisfactory in this age group, there is a need for evidence-based non-pharmacological treatment options. Our objectives were twofold: firstly, to synthesize published trials evaluating efficacy, safety and cost-effectiveness of psychological treatment of depression in the elderly and secondly, to assess the quality of evidence.METHOD: The electronic databases PubMed, EMBASE, Cochrane Library, CINAL, Scopus, and PsycINFO were searched up to 23 May 2016 for randomized controlled trials (RCTs) of psychological treatment for depressive disorders or depressive symptoms in people aged 65 years and over. Two reviewers independently assessed relevant studies for risk of bias. Where appropriate, the results were synthesized in meta-analyses. The quality of the evidence was graded according to GRADE (Grading of Recommendations Assessment, Development and Evaluation).RESULTS: Twenty-two relevant RCTs were identified, eight of which were excluded from the synthesis due to a high risk of bias. Of the remaining trials, six evaluated problem-solving therapy (PST), five evaluated other forms of cognitive behavioural therapy (CBT), and three evaluated life review/reminiscence therapy. In frail elderly with depressive symptoms, the evidence supported the efficacy of PST, with large but heterogeneous effect sizes compared with treatment as usual. The results for life-review/reminiscence therapy and CBT were also promising, but because of the limited number of trials the quality of evidence was rated as very low. Safety data were not reported in any included trial. The only identified cost-effectiveness study estimated an incremental cost per additional point reduction in Beck Depression Inventory II score for CBT compared with talking control and treatment as usual.CONCLUSION: Psychological treatment is a feasible option for frail elderly with depressive symptoms. However, important questions about efficacy, generalizability, safety and cost-effectiveness remain.
|
|
| 15. |
- Kennedy, Beatrice, et al.
(författare)
-
Oral Microbiota Development in Early Childhood
- 2019
-
Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 9
-
Tidskriftsartikel (refereegranskat)abstract
- Early life determinants of the oral microbiota have not been thoroughly elucidated. We studied the association of birth and early childhood characteristics with oral microbiota composition using 16 S ribosomal RNA (rRNA) gene sequencing in a population-based Swedish cohort of 59 children sampled at 6, 12 and 24 months of age. Repeated-measurement regression models adjusted for potential confounders confirmed and expanded previous knowledge about the profound shift of oral microbiota composition in early life. These alterations included increased alpha diversity, decreased beta diversity and alteration of bacterial composition with changes in relative abundance of 14 of the 20 most common operational taxonomic units (OTUs). We also found that birth characteristics, breastfeeding and antibiotic use were associated with overall phyla distribution and/or with the relative abundance of specific OTUs. Further, we detected a novel link between morning salivary cortisol level, a physiological marker of neuroendocrine activity and stress, and overall phyla distribution as well as with decreased abundance of the most common OTU mapped to the Streptococcaceae family. In conclusion, a major part of the maturation of the oral microbiome occurs during the first two years of life, and this development may be influenced by early life circumstances.
|
|
| 16. |
- Larsson, Ellinor, et al.
(författare)
-
An evidence map of digital tools to support social engagement in older adults living with mental illness or those who are at risk for mental health decline
- 2020
-
Ingår i: Gerontechnology. - : International Society for Gerontechnology. - 1569-1101 .- 1569-111X. ; 19:3, s. 1-29
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The use of digital technology might contribute to social engagement and mental health in an ageing population. Objective: To systematically map and describe the scientific knowledge and knowledge gaps on the effects of different types of digital tools for outcomes related to social engagement in older adults at risk for mental health decline. Methods: Thirteen groups of outcomes (domains) were defined, related to social engagement, by the use of digital tools. Thereafter, a systematic literature search was conducted in April 2017 to identify systematic reviews in line with the objective, an additional search for systematic reviews published since April 2017 was done in September 2019. In addition, reference lists as well as protocols from the Cochrane Collaboration and Campbell were searched. The final sample includes nine systematic reviews, published between 2012 and 2019, with both qualitative and quantitative results. Results: This evidence map shows that education in and use of digital tools, including computers and the internet, might decrease loneliness. Research is still limited, but the existing research points towards positive effects from the use of digital tools on outcomes related to social engagement, such as loneliness, social isolation, social interaction and/or social support, participation, depression, physical health/activities, as well as security, self-esteem or empowerment. Scientific knowledge gaps are present for the domains of quality of life, activities in daily living (ADL), cognition, autonomy, and usability. Conclusion: The evidence map shows inconclusive evidence about the effects on outcomes related to social engagement from the use of digital tools for older adults at risk of mental health decline or mental illness. More research is needed, and future research should include studies with a strong design, larger populations, and various subgroups of older adults in different contexts to further evaluate the effects of the digital tools related to social engagement for older adults at risk of mental health decline or mental illness.
|
|
| 17. |
- Larsson, Ellinor, et al.
(författare)
-
Välfärdsteknik - Digitala verktyg som social stimulans för äldre personer med eller vid risk för psykisk ohälsa : En kartläggning av systematiska översikter
- 2017
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- SyfteSyftet med SBU:s rapport är att kartlägga vetenskaplig kunskap samt vetenskapliga kunskapsluckor. Detta baseras på systematiska översikter som undersökt effekter, upplevelser eller erfarenheter av digitala verktyg som social stimulans för att minska eller förebygga psykisk ohälsa bland äldre personer. Vad tillför denna kartläggning? För äldre personer med eller vid risk för psykisk ohälsa finns det översikter som visar att utbildning i och användning av dator och internet kan minska ensamhet men evidensläget är svagt. Kunskapsluckor finns för domänerna livskvalitet, ADL-förmåga (Aktiviteter i det Dagliga Livet), kognition, självständighet samt användbarhet av tekniken.BakgrundVälfärdsteknik inrymmer digitala verktyg som syftar till att bibehålla eller öka trygghet, aktivitet, delaktighet eller självständighet för en person som har eller löper förhöjd risk att få en funktionsnedsättning. Välfärdsteknik kan fungera som ett hjälpmedel för den enskilde och utgörs av medicintekniska produkter alternativt konsumentprodukter vilka kan köpas i öppna handeln. Välfärdsteknik antas kunna bidra till ett aktivt och hälsosamt åldrande, även för åldrandeprocesser som sker genom hela livet och ter sig olika för varje individ.MetodEn systematisk kartläggning innebär att frågeställningen och domäner identifieras. Dessa ligger sedan till grund för en systematisk litteratursökning. Efter litteratursökningen identifieras, relevans- och kvalitetsbedöms systematiska översikter och slutligen sammanställs resultaten i de inkluderade systematiska översikterna. Kartläggningen inkluderar ingen kvalitetsbedömning av de studier som ingår i de systematiska översikterna. Denna kartläggning utgår från sju översikter av medelhög kvalitet från åren 2012 till 2017 och presenterar data från både kvantitativ och kvalitativ forskningsdesign. I kartläggningen görs ingen evidensgradering. Mer detaljerad information kring metod samt avgränsningar finns i rapporten.HuvudresultatI kartläggningen ingår sju systematiska översikter av medelhög kvalitet som visar på kunskap eller kunskapsluckor inom de identifierade domänerna.
|
|
| 18. |
- Mattsson, Claes, 1978-, et al.
(författare)
-
Design of a Micromachined Thermopile Infrared Sensor with a Self-Supported SiO2/SU-8 Membrane
- 2008
-
Ingår i: IEEE Sensors Journal. - Piscataway, USA : IEEE. - 1530-437X .- 1558-1748. ; 8:12, s. 2044-2052
-
Tidskriftsartikel (refereegranskat)abstract
- In the infrared region of the spectrum thermoelectric detectors such as the thermopile, are extensively used. These detectors rely on the well-known Seebeck effect, in which there is a direct conversion of thermoelectric differentials into electrical voltage. The temperature difference over thermocouple junctions is in general, created by forming a thin membrane connected to the silicon bulk. In many existing thermopiles, materials such as Si and Si3N4 have been used as membrane. These materials suffer from relatively high thermal conductivity, which lowers the membrane temperature and reduces the sensitivity of the detector. A material such as SU-8 2002 has a much lower thermal conductivity and is applied using standard photolithographic processing steps. This work presents thermal simulations regarding the use of SU-8 2002 as a thermal insulating membrane as compared to Si and Si3N4. The simulation results presented show that the temperature increase in a 5 µm SiO2/SU-8 membrane is about 9% higher than in a 1 µm Si3N4 membrane, despite the membrane thickness being increased by a factor of 5. A thermopile consisting of 196 serially interconnected Ti/Ni thermocouples positioned on a 5 µm SiO2/SU-8 2002 membrane has been fabricated. The sensitivity of the fabricated device has been evaluated in the infrared region, using a 1.56 µm IR laser and a xenon arc lamp together with a monochromator. The measurement results show a sensitivity of approximately 5 V/W over the wavelength range between 900 - 2200 nm. Measurements performed in a vacuum chamber show that the sensitivity of the detector could be increased by more than a factor of 3 by mounting the detector in a vacuum sealed capsule.
|
|
| 19. |
- Mattsson, Claes, et al.
(författare)
-
Development of an infrared thermopile detector with a thin self-supporting SU-8 membrane
- 2007
-
Ingår i: Proceedings of IEEE Sensors. - New York : IEEE conference proceedings. - 9781424412624 ; , s. 836-839
-
Konferensbidrag (refereegranskat)abstract
- In this paper we present the development and characterization of thermopile detector on a 4 mum thin self-supporting membrane made of the epoxy based photoresist SU-8. The membrane is realized using silicon bulk micromachining techniques. In many existing thermopile detectors, a temperature difference over the thermocouple junctions is achieved by connecting a thin membrane of either Si or Si3N4 to a silicon bulk. These materials suffer from relatively high thermal conductivity, which lowers the sensitivity of the detector. A material such as SU-8 has much lower thermal conductivity and is applied using standard photolithographic processing steps. Simulation results are presented which verifies SU-8 as a better choice than Si and Si3N4 when used as thermal insulating membrane in a thermopile detector. A thermopile consisting of 196 series coupled Ti/Ni thermocouples has been fabricated. Results from measurements are presented, showing a sensitivity of 5.6 V/W and a noise equivalent power (NEP) of 9.9 nW/radicHz.
|
|
| 20. |
- Mattsson, Claes, 1978-, et al.
(författare)
-
Fabrication and characterization of a design optimized SU-8 thermopile with enhanced sensitivity
- 2009
-
Ingår i: Measurement science and technology. - : IOP. - 0957-0233 .- 1361-6501. ; 20:11, s. 115202-
-
Tidskriftsartikel (refereegranskat)abstract
- In the infrared wavelength region, thermopiles are an important type of detectors. A major advantage of thermopiles is their non-cooling requirement. Depending on the applied absorption layer, their responsivity is often rather flat within a large wavelength region. This work presents the fabrication and characterization of a sensitivity and design optimized thermopile detector with a 4 µm self-supported SiO2/SU-8 membrane. The structure consists of 240 series interconnected thermocouple junctions obtained by a metal evaporation and lift-off. Two metal combinations have been evaluated, namely, nickel/titanium and aluminium/bismuth. Series resistances of 76 k and 283 k were measured for the Ni/Ti thermopile and the Al/Bi thermopile respectively. For the Al/Bi thermopile a responsivity of 60 V/W was achieved using a 1.56 µm fibre coupled diode laser with a power of 3.5 mW. Using a white light source with a radiation flux of 0.45 W/mm2 a voltage response of 68 V mm2/W was measured for the Al/Bi thermopile. The time constant of the characterized detectors was calculated as being 70 ms, using the pulsed IR laser.
|
|
| 21. |
- Mattsson, Claes, et al.
(författare)
-
Fabrication and evaluation of a thermal sensor formed on a thin photosensitive epoxy membrane with low thermal conductivity
- 2008
-
Ingår i: PROCEEDINGS OF THE 17TH INTERNATIONAL VACUUM CONGRESS/13TH INTERNATIONAL CONFERENCE ON SURFACE SCIENCE/INTERNATIONAL CONFERENCE ON NANOSCIENCE AND TECHNOLOGY. - : Institute of Physics (IOP). ; , s. 082048-
-
Konferensbidrag (refereegranskat)abstract
- This article present the fabrication and development of a thin metal film bolometer IR detector connected in a Wheatstone bridge configuration. The bolometer is constructed on a 4 μm thin self-supported SU-8 2002 membrane. A polymer material such as SU-8 has low thermal conductivity and is applied using standard photolithographic processing step, and this could increase detector sensitivity and lower the production cost. Thermal simulation results are presented, which verifies SU-8 as a better choice of materials compared to common membrane materials such as Si and Silicon nitride. Measurements on the fabricated nickel resistance bolometer on SU-8 2002 membrane show a sensitivity of 9.3 V/W when radiated by an IR laser with a wavelength of 1.56 μm.
|
|
| 22. |
- Mattsson, Claes, et al.
(författare)
-
Manufacturing and characterization of a modified four-quadrant position sensitive detector for out-door applications
- 2004
-
Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : ELSEVIER SCIENCE BV. - 0168-9002 .- 1872-9576. ; 531:1-2, s. 134-139
-
Tidskriftsartikel (refereegranskat)abstract
- Position sensing detectors (PSDs) are useful in many applications such as vibration, displacement and triangulation measurements. In this paper we have constructed a novel structure, which has higher inter-electrode resistance than a lateral effect PSD and is more robust to atmospheric turbulence than a conventional four-quadrant PSD (Nuclear Instruments and Methods in Physics Research A 466 (2001) 183). The detector structure is useful for applications with detector windows less than 0.5 x 0.5 mm(2), but the nonlinearity is the main concern for a detector of that size. Without any corrections for non-linearity the standard deviation of the error is 9 mum (2.2%). Using a simple analytical expression and a 2-d correction-function stored in a look-up table the positioning error is reduced to 6 (1.5%) and 2 (0.5%) mum, respectively.
|
|
| 23. |
- Mattsson, Claes, 1978-, et al.
(författare)
-
Thermal simulation and design optimization of a thermopile infrared detector with SU-8 membrane
- 2009
-
Ingår i: Journal of Micromechanics and Microengineering. - : IOP Publishing. - 0960-1317 .- 1361-6439. ; 19:5, s. 055016-
-
Tidskriftsartikel (refereegranskat)abstract
- Simulation and optimization tools are commonly used in the design phase of advanced electronics devices. In this work, we present a thermal simulation and design optimization tool for infrared thermopile detectors based on a closed membrane structure. The tool can be used to simulate and optimize thermopile detectors with an arbitrary number of design parameters. The optimization utilizes the Nelder–Mead and the adaptive simulated annealing optimization algorithms to maximize the system performance. A thermopile detector with an SU-8-based closed membrane and metal–metal thermocouples has been simulated and optimized. Based on the results generated by the tool, an optimized detector has been fabricated and characterized. The results from the measurements presented are in good agreement with the simulation results.
|
|
| 24. |
- Nordberg, Gunnar F, et al.
(författare)
-
Lung function in volunteers before and after exposure to trichloramine in indoor pool environments and asthma in a cohort of pool workers
- 2012
-
Ingår i: BMJ Open. - : BMJ Publishing Group. - 2044-6055. ; 2:5, s. e000973-
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Exposure to trichloramine (NCl(3)) in indoor swimming-pool environments is known to cause mucous membrane irritation, but if it gives rise to changes in lung function or asthma in adults is not known. (1) We determined lung function in volunteers before and after exposure to indoor pool environments. (2) We studied the occurrence of respiratory symptoms and asthma in a cohort of pool workers.DESIGN/METHODS/PARTICIPANTS: (1) We studied two groups of volunteers, 37 previously non-exposed healthy persons and 14 pool workers, who performed exercise for 2 h in an indoor pool environment. NCl(3) in air was measured during pool exposures and in 10 other pool environments. Filtered air exposures were used as controls. Lung function and biomarkers of pulmonary epithelial integrity were measured before and after exposure. (2) We mailed a questionnaire to 1741 persons who indicated in the Swedish census 1990 that they worked at indoor swimming-pools.RESULTS: (1) In previously non-exposed volunteers, statistically significant decreases in FEV(1) (forced expiratory volume) and FEV(%) (p=0.01 and 0.05, respectively) were found after exposure to pool air (0.23 mg/m(3) of NCl(3)). In pool workers, a statistically significant decrease in FEV(%) (p=0.003) was seen (but no significant change of FEV(1))(.) In the 10 other pool environments the median NCl(3) concentration was 0.18 mg/m(3). (2) Our nested case/control study in pool workers found an OR for asthma of 2.31 (95% CI 0.79 to 6.74) among those with the highest exposure. Exposure-related acute mucous membrane and respiratory symptoms were also found.CONCLUSIONS: This is the first study in adults showing statistically significant decreases in lung function after exposure to NCl(3). An increased OR for asthma among highly exposed pool workers did not reach statistical significance, but the combined evidence supports the notion that current workroom exposures may contribute to asthma development. Further research on sensitive groups is warranted.
|
|
| 25. |
- O'Nils, Mattias, et al.
(författare)
-
A Project Based Master's Programme for SoF/SoC based Sensor Systems
- 2005
-
Ingår i: Proceedings of the 2005 European Conference on Circuit Theory and Design. - : IEEE conference proceedings. - 0780390660 ; , s. 123-126
-
Konferensbidrag (refereegranskat)abstract
- We forsee an increase in communicating sensor systems, that we call Sensible Things that Communicate (STC). These systems range from simple powerless systems for control or classification. In this paper we present the curriculum and pedagogical methods used in a Master's programme developed to meet the requirements that STC systems put on a designer. The goal for the program has been to encurage the students to acquire knowlege from completing practical design cases, of industrial or academic interest. This has shown to be an effective method to learn an motivate the students.
|
|
| 26. |
|
|
