| 1. |
- Brännström, Inger, 1945-
(författare)
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Community participation and social patterning in cardiovascular disease intervention
- 1993
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This study addresses health policy and public health in the field of cardiovascular disease (CVD) on the local level in Sweden. The overall aim is to contribute to the assessment of structural and social conditions within public health by analysing participation processes and outcome patterns in a local health programme. The northern Swedish MONICA study served as a reference area. The research strategy has been to integrate quantitative and qualitative methodologies and, thereby, focus on different aspects of the health programme under study.The mortality rate was excessive in the study area of Norsjö relative to both provincial and national figures over a period of more than 10 years. This finding formed the basis for a tenyear comprehensive and community-based health programme towards the prevention of CVD and diabetes.Even in this seemingly homogeneous area it was found that socio-economic circumstances were associated with the public health. Almost half of the study population had hypercholesterolaemia (;>6.5 mmol/1), 19% of men and 25% of women were smokers and 30% and 29%, respectively, had high blood pressure. Age had a strong impact on all outcome measures. After adjustments for age and social factors it was found that the relative risk of having hypercholesterolaemia dropped significantly in both sexes during the six years of intervention. The probability of being a smoker was significantly reduced only in highly educated groups. No statistically significant change over time could be found for the risk of suffering high blood pressure. In the reference area of northern Sweden there were no changes over time for any of the selected risk factors. The likelihood of self-assessed good health decreased with increasing risk factor load, with the exception of hypercholesterolaemia , in all social strata.The authorities, including the health and medical staff, were the main actors on the mediastage. Men in manual occupations were least affected by the media coverage. The actors and the public as well as the media viewed the health programme as orientated towards individual lifestyles. Community participation was mainly defined by the actors based on the medical and health planning approach. Differences in interpretations, social interests, personal conflicts and ideological constraints among the actors at local level were observed. Some critical attitudes towards the organization and management of the health programme were also noted among the citizens. However, a majority of the public wanted the health programme to continue. The present study underlines the importance of considering age, gender and social differences in the planning and evaluation of CVD preventive programmes.
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| 2. |
- Eriksson, Leif
(författare)
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Knowledge Translation in Vietnam : Evaluating facilitation as a tool for improved neonatal health and survival
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Neonatal mortality remains a problem worldwide, despite the existence of low-cost and evidence-based interventions. Unfortunately, the translation of these interventions into practice is deficient.The aim of this thesis was to study aspects of knowledge translation (KT) before and during the Neonatal Knowledge Into Practice (NeoKIP) trial in Quang Ninh, Vietnam. Over a period of three years, this trial evaluated the use of facilitators from the Women’s Union who supported maternal and newborn health groups (MNHG) comprised of eight local stakeholders, as an intervention for improved neonatal survival.In the first two studies (before intervention) we assessed primary health care staff’s knowledge and material preparedness regarding evidence-based neonatal care and explored how primary health care staff translated knowledge into practice. The last two studies (during intervention) were process evaluations aimed at describing the implementation, process and mechanism of the NeoKIP intervention.Primary health care workers achieved 60% of the maximum score in the knowledge survey. Two separate geographical areas were identified with differences in staff levels of knowledge and concurrent disparities in neonatal survival, antenatal care and post-natal home visits. Staff perceived formal training to be the best way to acquire knowledge but asked for more interaction between colleagues within the healthcare system. Traditional medicine, lack of resources, low workload and poorly paid staff constituted barriers for the development of staff knowledge and skills.Eleven facilitators were trained to cover eight facilitator positions. Of the 44 MNHGs, 43 completed their activities to the end of the study. In total, 95% of the monthly meetings with a MNHG and a facilitator were conducted with attendance at 86%. MNHGs identified 32 unique problems, mainly families’ knowledge/behavior, and implemented 39 unique actions, mostly regarding communication. MNHGs experienced that the group was strategically composed to influence change in the communes and facilitators were identified as being important to sustaining activities over time. The facilitators’ lack of health knowledge was regarded as a deficit in assisting the MNHGs, but their performance and skills increased over time.This low-cost model, building on local stakeholder involvement, has the capacity to be scaled up within existing healthcare structures.
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| 3. |
- Lindström, Emma, 1978-
(författare)
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Nutrition and Oxidative Parameters in Pregnancy, Size at Birth and Metabolic Status of the Offspring at 4.5 Years : The MINIMat Trial in Rural Bangladesh
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Undernutrition and oxidative stress in fetal life and infancy may lead to adverse health outcomes in the offspring. We studied nutrition and oxidative parameters in pregnancy and their associations with birth anthropometry and metabolic status in the children.In Matlab in rural Bangladesh, women were randomized to either early (Early) invitation to food supplementation or to start at their own liking (Usual). Women were also allocated to either; 1) 60 mg iron and 400 µg folic acid (Fe60F), 2) multiple micronutrients including 30 mg iron and folic acid (MMS), or 3) 30 mg iron and folic acid (Fe30F). Micronutrients (hemoglobin, iron, zinc, folic acid, vitamin B-12) were assessed in pregnancy week 14, lipid peroxidation in week 14 and 30, and DNA oxidation in week 19. The offspring were assessed for anthropometric measurements at birth and metabolic status at 4.5 years.Micronutrient deficiencies were common with zinc and vitamin B-12 deficiency being most prevalent. Anemia was present in approximately one third of women, however, iron deficiency was uncommon seen in only 2%.Maternal Early food supplementation group resulted in an improved lipid status in the children at 4.5 years compared to Usual food group. Prenatal use of MMS lowered the children’s glucose, insulin, HOMA-IR, and growth factors compared to Fe60F. Lipid peroxidation in early pregnancy was associated with size at birth and insulin and HOMA-IR levels in the children. Lipid peroxidation in late pregnancy, however, was associated with the children’s lipid status. Both increasing lipid peroxidation and increasing DNA oxidation was associated with decreasing IGF-1 levels. The beneficial effects of an Early start of food supplementation show that an improved prenatal nutrition may have lasting effects in the offspring and highlights the importance of early timing food supplementation. Use of MMS, however, resulted in lower insulin levels, which, considering the already low level of insulin in these children, may be a cause of concern. MMS also resulted in growth factors indicative of slower growth and further research appears to be needed before scaling up the use of MMS. Oxidative parameters in pregnancy were associated with longer-term outcomes in the offspring, suggesting that oxidative stress may be involved in the development of later metabolic disease.
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| 4. |
- Målqvist, Mats, 1971-
(författare)
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Who can save the unseen? : Studies on neonatal mortality in Quang Ninh province, Vietnam
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Globally, neonatal mortality has remained basically unchanged for the last three to four decades and every year almost four million newborns die before reaching one month of age. This persistent mortality is related to an invisibility of the newborn child in policies and statistics and a neglect of health care decision-makers, planners and practitioners to deliver a perinatal continuum of care. In recent years attention has however been brought to the unchanged neonatal mortality in an effort to improve survival. The present thesis seeks to increase understanding of obstacles for better neonatal survival. The studies performed are undertaken as sub-studies to the NeoKIP project in Quang Ninh province in northern Vietnam, a randomized controlled trial of knowledge implementation for improved neonatal survival (Neonatal Health – Knowledge Into Practice, ISRCTN 44599712). In the first paper we investigated and discussed the scope of invisibility of neonatal mortality through measuring the accuracy of official statistics on neonatal deaths. The second paper reports an inquiry of determinants of neonatal mortality by use of a population-based case-referent design. Paper III and IV analyse delivery care utilization and care seeking patterns prior to and at delivery using narratives and GIS technique. There was a substantial under-reporting of neonatal mortality in the official statistics, with study results showing a four times higher neonatal mortality rate in Quang Ninh province than reported to the Ministry of Health. This neonatal mortality rate of 16/1000 live births (as compared to 4.2/1000 in official reports) was unevenly distributed in the province, showing large geographical discrepancies. In the rural and remote areas of Vietnam education level is lower and the concentrations of ethnic minorities and poor households are higher. Ethnic minority belonging was associated with a more than doubled risk of neonatal death compared to the hegemonic group of Kinh (OR 2.08 CI 95 % 1.39 – 3.10). This increased risk was independent of household economic status or maternal education level. Neonatal mortality was also associated with home deliveries, non-attendance to antenatal care and distance to the health care facilities. However, ethnic minority mothers still had an increased risk of experiencing a neonatal death even if they attended antenatal care, delivered at or lived close to a health facility. The invisibility of the neonatal period in health information systems hides the true width of the neonatal mortality challenge. By not acknowledging the problem, the marginalization of already disadvantaged groups continues, leaving ethnic minority babies with an elevated risk of dying during the first month in life. This example of ethnic inequity highlights the importance to target those most in need. The studies of the present thesis should therefore be looked upon as a contribution to the struggle to illuminate the global burden of neonatal mortality.
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| 5. |
- Omer-Salim, Amal, 1964-
(författare)
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Mothers’ Agency in Managing Breastfeeding and Other Work in Dar es Salaam, Tanzania and New Delhi, India
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Combining breastfeeding and other forms of work is desirable from both public health and labour productivity perspectives. This is often challenging, especially in low- or middle-income fast-growing urban settings. The aim of this thesis was to gain a deeper understanding of mothers’ perspectives on combining breastfeeding and other work in the urban contexts of Dar es Salaam, Tanzania, and New Delhi, India. Individual semi-structured interviews were conducted with community mothers (n=8) and health worker mothers (n=12) in Dar es Salaam, and mothers working in the health (n=10) and education sectors (n=10) in New Delhi. The methods of analysis were: qualitative content analysis, grounded theory approach, and directed and general inductive content analyses. Mothers’ agency manifested in several ways. Striving to integrate or segment the competing domains of home and work was a goal of these mothers to reduce conflicts in managing breastfeeding and other work. Spatial and time constraints led mothers to engage in an array of carefully planned actions and troubleshooting tactics that included ways of ensuring proximity between them and their baby and efficient time managing. The timing of these strategic actions spanned from pregnancy, over maternity leave, to the return to employment. Managing breastfeeding and work triggered emotions such as stress, frustration and guilt, but also satisfaction and joy. Mothers negotiated with family, employers, colleagues and informal networks to gain support for their strategies, displaying both individual, collective and proxy agency. Changing family structures and roles highlight the potentially greater supportive role of the partner/husband. Work/Family Border Theory and Bandura’s agency constructs provided frameworks for a deeper understanding of mothers’ perspectives, but using existing family relationship constructs would better diffentiate between various modes of agency. Workplaces and maternity protection conditions were generally inadequate. Interventions are required: to strengthen the breastfeeding mother’s own agential capacity using an individual approach; to provide information to families and communities; to improve regulatory, structural and attitudinal conditions at workplaces, and to strengthen health and social services to adequately support mothers in managing breastfeeding and other work.
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| 6. |
- Shaheen, Rubina, 1964-
(författare)
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Prenatal food and micronutrient supplementation to malnourished women in Bangladesh : Effects, Equity, and Cost-effectiveness
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Maternal nutrition is closely linked to child health and survival. In Bangladesh there is a high prevalence of undernutrition in the form of chronic energy deficiency [CED, Body Mass Index <18.5 (kg/m2)] in women and low birth weight. The aims of this thesis are to explore women’s perceptions of maternal undernutrition, to analyse the association between prenatal food supplementation and birth weight (BW), to analyse whether food- and multiple micronutrient interventions generate pro-disadvantaged equity in child survival, and to examine whether an early prenatal invitation to food supplementation and multiple micronutrient supplements (MMS) represents value for money in infant survival compared to invitation to food supplementation at usual time combined with 60 mg iron and 400 µg folic acid (standard practice).The study on women’s perceptions (n=236) was nested into the MINIMat randomized trial where women (n=4436) were allocated to early (E), or usual (U) time of invitation to prenatal food supplementation and 30 mg iron with 400 µg folic acid, or 60 mg iron with 400 µg folic acid, or MMS. Live births (n=3625) were followed-up. The analyses of equity and cost-effectiveness were based on this trial. A cohort design (n=619) was employed for the analysis of food supplements and BW.Women perceived maternal undernutrition as a serious health problem and attached very low scores to CED in pregnancy. An average of four months of prenatal food supplementation increased BW by 118 g. An early invitation to prenatal food supplementation and MMS lowered mortality in children before the age of five years and reduced social disparity in child survival chances. An increment from standard practice to E-MMS averted one extra infant death at a cost of US$797 to US$907, and saved one extra life year at a cost of US$27 to US$30.High priority should be given to the nutritional status of pregnant women in societies where undernutrition and food insecurity occurs. Prenatal food supplementation has the potential to significantly increase BW, and an early initiation of prenatal food supplementation combined with MMS was considered cost-effective in lowering infant mortality and increase social equity in child survival chances.
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| 7. |
- Sohel, Nazmul, 1962-
(författare)
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Epidemiological and Spatial Association between Arsenic Exposure via Drinking Water and Morbidity and Mortality : Population based studies in rural Bangladesh
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The overall aim of this thesis is to evaluate the risk for increased morbidity and mortality due to long-term arsenic exposure via drinking water by use of epidemiological and spatial approaches in studies performed in Matlab, Bangladesh. A total of 166,934 individuals aged 4 years and above were screened for skin lesions in 2002-2003. Another sample of 115,903 adults aged 15 years or more and a third sample of 26,972 pregnancies in 1991-2000 were considered in a historical cohort and an ecological study, respectively, where risk of adult mortality and spatial clusters of foetal loss and infant death were analysed in relation to arsenic exposure. More than 70% of the tube-wells in the study area exceeded the threshold for arsenic contamination according to the WHO guideline (10 µg/L). The prevalence of arsenic-induced skin lesions was 3/1000 and men had significantly higher prevalence of skin lesions (SMR 158, 95% CI: 133-188) compared to women. There was an increased risk for death in adulthood due to all non-accidental causes (hazards ratio = 1.16, [95% CI 1.06-1.26]) even at a low level of arsenic contamination (10-49 µg/L). Slightly lower risks were observed for death in cancers (1.44 [1.06-1.95]) and infectious diseases (1.30 [1.13-1.49]) at 50-149 µg/L, but for cardiovascular diseases, it was evident (1.23 [1.01-1.51]) from the level 150-299 µg/L. A dose-response relationship was observed for each of these causes. We identified high and low risk clusters of foetal loss and infant death that coincided with identified high and low clusters of arsenic exposure. Water arsenic concentration of the reported main water source was significantly correlated with arsenic concentration in urine, which reflects current arsenic intake from all sources (R2=0.41, ρ< 0.0001), and the influence of neighbouring water sources was minimal. The study findings underlines that the ongoing arsenic exposure has resulted in a series of severe public health consequences in Bangladesh that call for reinforcement in the mitigation efforts. Knowledge about the spatial distribution of exposure and health effects may be of value in that process.
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| 8. |
- Wallby, Thomas, 1956-
(författare)
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Lika för alla? : Social position och etnicitet som determinanter för amning, föräldrars rökvanor och kontakter med BVC
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Child Health Services (CHS) in Sweden are offered free of charge to all Swedish parents with children 0-5 years of age. The regular service schedule includes home visits, health examinations, vaccinations and participation in parenting groups. The CHS should pay extra attention to disadvantaged families. The aim of this thesis was to investigate to what extent the CHS reaches groups of families with special needs, e.g. immigrant families, low income families, young and single mothers, with universal or selective measures, as well as to investigate the variation of two determinants of child health, second hand smoke and breastfeeding, in these groups of families. The thesis also aimed at investigating validity of data in the county CHS quality database (Basta). The thesis is based on data from Basta together with several national registers. The CHS equally reached all families with infants with the universal program except for participation in parenting group. Foreign born, young, single and low-income mothers had lower participation rates. Smoking rates were lower in foreign-born than in Swedish-born mothers and higher for foreign-born than in Swedish-born fathers. Smoking was more common among single and low income parents and young mothers. Young and single mothers had lower breastfeeding rates at 6 months. At 12 months the breastfeeding rates were higher among foreign-born mothers. The validity test of data in the Basta database showed sensitivity values for immunizations, breastfeeding and smoking at 90-100 % and for any home visit, participation in parenting group at any time, a minimum number of 6 visits at the Child Health Centre (CHC) and a minimum number of 11 visits at the CHC at 88 - 96 %. The sensitivity value for the exact match of number of CHC visits (+/- 3 visits) was 88 %. Conclusions: The universal programme was equally distributed in different immigrant and socio-demographic populations. However, the results did not indicate equality according to the assumption that some families need more input than others in order to achieve equity of outcome. Individual data routinely collected from CHS records to a quality database provides data of good quality that can be used for both quality surveillance and research.
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| 9. |
- Nahar, Baitun
(författare)
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Effects of Food Supplementation and Psychosocial Stimulation on Growth and Development of Severely Malnourished Children : Intervention Studies in Bangladesh
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Early childhood malnutrition is a global public health problem with serious short- and long-term consequences. The aim of this thesis is to evaluate the effects of psychosocial stimulation (PS) with or without food supplementation (FS) on growth and development of severely malnourished children, quality of home environment, mother’s child-rearing practices and depressive symptoms. The study setting was Dhaka, Bangladesh, and the participants were severely malnourished children, aged 6-24 months, admitted at Dhaka Hospital of the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B). A hospital-based study was conducted in Nutrition Rehabilitation Unit of ICDDR,B hospital, where a control group (n=43) was studied initially, followed by an intervention group (n=54). All received standard nutrition rehabilitation care. The intervention group received daily group meetings and play sessions in the hospital, and was thereafter visited at home for 6 months. A community-based randomised trial was conducted including children (n=507) admitted at hospital for initial treatment of an acute infection, and thereafter assigned to PS, FS, PS+FS, clinic control or hospital control groups. PS was delivered at follow-up visits, fortnightly for 6 months at community clinics. FS included distribution of cereal-based food packets (150–300 kcal/day depending on age) for 3 months. All groups received standard medical care and micronutrient supplementation. In the hospital-based study, the intervention group had significantly higher scores in mental (p<0.001, effect size 0.52 SD) and motor development (p=0.047, effect size 0.37 SD), and weight (p=0.03, effect size 0.39 SD), after 6- months intervention. In the community-based trial, there was a significant effect of stimulation after six months of intervention on children’s mental development (group*session interaction p=0.037, effect size=0.37 SD) and weight (group*session interaction p=0.02, effect size=0.26 SD) but no effect on motor development or linear growth. The PS+FS and PS groups differed in total HOME score, two HOME subscales (maternal involvement and play materials), and in mother’s child- rearing practices scores but not in depressive symptoms. PS with or without FS had small improvement on children’s growth and development, quality of home environment and mother’s rearing-practices of severely malnourished children. More intensive interventions with longer duration are therefore recommended.
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| 10. |
- Rahman, Anisur, 1962-
(författare)
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Prenatal Arsenic Exposure and Consequences for Pregnancy Outcome and Infant Health : Epidemiological Studies in Bangladesh
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this thesis was to analyse possible effects of prenatal arsenic exposure on foetal and infant health. The setting is Bangladesh, where two cohorts were studied, both part of a health and demographic surveillance system in Matlab. A historical cohort 1991-2000 included 29,134 pregnant women with information on drinking water sources and arsenic testing of tube well water. A prospective cohort study included pregnant women 2002 - 2003 where urinary arsenic concentrations were assessed twice during pregnancy; 2,924 women and their pregnancy outcomes were evaluated for foetal loss, perinatal and infant mortality; 1,578 mother-infant pairs were analysed for size at birth; and 1,552 were analysed for morbidity during infancy. Women exposed to arsenic levels ≥ 50 µg/L in water had an increased risk of foetal loss and infant death in comparison with women exposed to arsenic levels < 50 µg/L. These findings were confirmed in the prospective cohort study. Women with urine arsenic concentrations at the 5th quintile had 62% increased risk of spontaneous abortion (OR 1.62, 95% CI 1.04 - 2.55) in comparison with women who had arsenic concentrations at the 1st quintile level. Increased risks of perinatal morality (RR 3.01, 95% CI 1.07 - 8.45) and infant mortality (RR 5.01; 95% CI: 1.41 - 17.84) were also observed at the 5th quintile of exposure. Significant negative dose-effect associations were found between arsenic exposure and birth weight, head and chest circumferences at a relatively low level of exposure (<100 µg/L in urine). In this range of exposure birth weight decreased by 1.68 g (SE 0.62) for each 1 µg/L increase of arsenic in urine. In comparison with exposure at the 1st quintile level the risk of lower respiratory tract infection was significantly increased (RR 1.68, 95% CI 1.35-2.07) for women who had urinary arsenic concentrations at the 5th quintile level. The risk was also increased for diarrhoeal diseases. The study findings highlight the negative effects of arsenic exposures on pregnancy outcomes and infant health. Mitigation programs need to be strengthened and women of reproductive ages should be prioritized in arsenic affected regions worldwide.
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| 11. |
- Alwin, Jenny, 1978-
(författare)
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Assessment of Support Interventions in Dementia : Methodological and Empirical Studies
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Dementia means a continuous deterioration of abilities and has a large impact on the persons affected as well as on family members and others close to the persons with dementia. Interventions aimed at this population in order to support and alleviate the often straining situation may be of great importance. There is a need to increase the knowledge and understanding of the impact and consequences of these interventions, both at an individual level and at a societal level. The demand for information concerning, e.g., economic and medical impact of technologies and interventions within health care is increasing. Assessment of technologies and interventions in dementia is related to certain methodological issues. The overall aim of this thesis is to contribute to the development of methodological knowledge concerning assessment studies and understanding of support interventions in dementia.This thesis work includes four studies that examine methodological aspects of assessment of support interventions in dementia and also report empirical research on the perception of support interventions from the perspectives of family caregivers of persons with dementia. In study I, an assessment model for assistive technology (AT) interventions in dementia was developed. In study II, part of the assessment model is applied, and a process evaluation of the AT intervention is presented. Study III examines family caregivers’ perception of the importance of different types of support and services. In the final study, study IV, a well‐acknowledged methodological challenge within the field of assessment in dementia is addressed: measuring health‐related quality of life (HRQoL). The studies are based on different data materials.An assessment model of AT interventions was developed that includes health economic evaluation from a societal perspective as well as evaluation of the intervention process. The perspectives of both persons with dementia and their relatives were incorporated in the model. The process evaluation was applied in study II in order to study the relatives’ perception of an AT intervention process. Assistive technology interventions in dementia may be of great significance for the relatives. By performing the process evaluation, several important aspects that need to be acknowledged in AT intervention processes in dementia were identified.Family caregivers of persons with dementia perceived different types of support/services within the comprehensive areas of counselling, relief and information as very important. Knowledge of the caregivers’ preferences is significant so that more directed support interventions may be provided.One specific methodological issue was addressed in study IV. The results of study IV showed that there were large differences in the results of cost‐effectiveness analyses depending on whether patient self‐ratings or proxy ratings (ratings of persons close to the patient) of patient HRQoL were used for the same analysis. These differences in the results could ultimately have an important impact on decision making and resource allocation.Support interventions aimed at persons with dementia and their relatives may be of great value. Conducting assessment studies of technologies and interventions within health care is important in order to increase the knowledge concerning, e.g., economic and medical impact. Assessment studies of support interventions dementia entails methodological issues that need to be addressed. There is a need for increased knowledge within this field and suggestions on methodology are made.
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| 12. |
- Bogatic, Wirginia, 1969-
(författare)
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Exilens dilemma: att stanna eller att återvända : Beslut i Sverige av polska kvinnor som överlevde KZ-lägret Ravensbrück och räddades till Sverige 1945-1947
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is about the intersection of great narratives and individual decisions. In the intersection, the dilemma of exile is discussed: to remain in exile or return to one’s homeland. The decision to remain or return was made by the surviving Polish female concentration camp prisoners that were brought back to Sweden in 1945 with the Red Cross rescue operation.The women’s decisions have been contextualized by being placed against the political, social and economic upheavals that took place primarily in Poland, but also partly in Sweden, as well as in the international environment with which the new Poland had to form a relationship following the Second World War.The thesis moves between three levels: the micro level, comprising the individuals, their choices and experiences; the macro level, including the surrounding social, economic and political structures; the meso level, which merges the individual, her network and the state. The theoretical framework is on the one hand based on Reinhart Koselleck’s concepts of “realm of experience” and “expectations” that structure the time horizon and refer to the universal, and on the other hand, the sociological concept of generations and Svante Lundberg's model of exile with the concepts of Circumstance, Frame and Meaning. Both Koselleck and Lundberg focus on the individual / group and structural context. Sources used have been material from the Swedish Government and the two Polish governments and their agencies. In addition, a number of Polish and Swedish newspapers published during the period 1945-1947 as well as material from the Polish Source Institute in Lund (PIZ) have been studied. Thirteen in-depth interviews with the surviving women (both in Poland and Sweden) have been carried out, resulting in so-called life stories, with the objective of providing an answer to the question of why some of them remained in Sweden after the war while others returned to Poland. In the women's life stories, some themes can be distinguished: the common realm of experience, being adherent to the same sociological generation with a manifest collective memory (which in part developed differently depending on their decisions to remain or return), a link between war and captivity and expectations for the future. Otherwise, the life stories highlight the women's construction of identity, which is affected by growing up in the between-war Poland, the time during World War II and the occupation. It also reveals that these experiences influenced their decision: remaining and returning.
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| 13. |
- Chopra, Mickey, 1967-
(författare)
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Prevention of Mother to Child Transmission of HIV in Africa : Operational Research to Reduce Post-natal Transmission and Infant Mortality
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis assesses the effectiveness of the National Prevention of Mother to Child Transmission of HIV (PMTCT) programme in 3 sites in South Africa, and the quality of infant feeding counselling across four countries, Botswana, Kenya, Malawi and Uganda . Implementation and outcome of PMTCT services were very different across the 3 sites. The Paarl site is achieving results comparable to clinical trial studies with a HIV-free survival rate of 85% at 36 weeks, while Umlazi is somewhat lower (74%) and Rietvlei, with HIV-free survival of 64%. Maternal viral load, prematurity and site were independent risk factors for infection and/or death. The regression analysis suggests that some of this difference is explained by the differences in quality of health systems across the sites. Traditional risk factors (e.g. viral load, prematurity) do not seem to explain the substantial differences in HIV-free survival between the Paarl and Rietvlei sites.The overall mortality rate for HIV exposed infants in this cohort was 155 per 1000 live births at 36 weeks, a level higher than most other HIV exposed cohorts. The excess mortality is occurring almost completely amongst HIV infected infants who had a nine fold increased risk of mortality compared with HIV exposed but HIV negative infants. There was no significant difference in 36 week survival rates between those HIV exposed but uninfected infants and those who were not HIV exposed, Hazard ratio 0.7 (95% CI 0.3-1.5).With respect to HIV and infant feeding most health workers across the four countries (234/334, 70%) were unable to correctly estimate the transmission risks of breastfeeding. Exposure to PMTCT training made little difference to this. Infant feeding options were mentioned in 307 out of 640 (48%) observations of PMTCT counselling session and in only 35 (5.5%) were infant feeding issues discussed in any depth; of these 19 (54.3%) were rated as poor. South Africa was similar with only two out of thirty four HIV positive mothers being asked about essential conditions for safe formula feeding before a decision was made. This body of work has demonstrated that the gap between efficacy and effectiveness can be significant.
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| 14. |
- Goldin, Stephen, 1948-
(författare)
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Living in the present with the past : mental health of Bosnian refugee children in Sweden
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The negative impact of war on child mental health has been repeatedly documented. Still, the majority of children exposed to ethnic and political violence show no signs of clinical disorder. In Western countries of exile, these findings have prompted a variety of attempts to evaluate refugee children, in the hope of identifying and offering support to those children “at risk”. This study critically examines one such attempt. The aims are fourfold: 1. to describe the range and pattern of child trauma-stress exposure and mental health reactions as captured on clinician semi-structured interview; 2. to critically compare clinician assessment with independent parent, child and teacher reports; 3. to identify factors of potential risk or protective import for child mental health; 4. to draw clinical implications: from whom and by what means can children at risk be reasonably identified? The target of our study was the entire population of Bosnian-Serbian-Croatian speaking child refugee families assigned to Umeå and surrounding municipalities during 1994-95. Fifty families, containing 90 children aged one month to 20 years, were included in the study. Assessment occurred in two phases. First, a semi-structured interview was conducted that inquired broadly as to the child’s family background, trauma-stress exposure, emotional-behavioral problems, patterns of family functioning, and future hopes. Second, standardized self-report questionnaires were administered, separately to parent and child, to provide alternative appraisal of the child’s war exposure, mental health symptoms, coping strategies, and social network. Teacher evaluation of child cognitive-social functioning as well as emotional-behavioral problems was also obtained. Clinician semi-structured interview revealed the child’s pre-war period as preponderantly good, and provided richly detailed narratives of child exposure during war and resettlement that clustered into a limited number of type-stories. Independent parent assessment captured the same broad strokes of child war exposure; but both approaches – fixed questionnaire and semi-structured interview – showed specific areas of blindness. Teenage self-report offered a disparate but equally rich account of war exposure, while that of primary school child was significantly less detailed. Nearly half of the study children (48%) were identified on clinician interview with one or more mental health problem “demanding further attention”. Depressiveness was the single most prevalent symptom (31%), followed by posttraumatic reactions (23%) and anxiety-regressiveness (15%). Independent symptom appraisal by parent and primary school child was largely concordant with that of clinician, while teenagers made similar assessment as to who was in distress, but defined the nature of that distress differently. Teacher report stood apart, identifying fewer inward emotional problems and asserting the cognitive-social competence of the vast majority of study children. Trauma-stress exposure during both war and resettlement presented as an unequivocal risk to mental health, but accounted for only part of outcome variance. Additional factors of strong import related broadly to “living in the present”. Parent impairment of daily routines, child dissatisfaction with school and an ongoing quarrelsome relationship presented as risk factors. Protection was associated with parent maintenance of a warm family climate and of concrete physical-emotional caring, child social ties to physically present others, including teacher; and above all, a family sense of hope for the future. Results support the general robustness of our semi-structured approach. Exploring the child’s present well-being in narrative relation to past and future, our assessment captured and gave meaning to the complexity of child exposure and behavior. At the same time, independent parent and child appraisals provided an additional richness to the retelling and evaluation of child experience. Particularly the apartness of teacher report underscores the need to incorporate an outside-world vantage point in the process of risk assessment.
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| 15. |
- Musafili, Aimable, 1972-
(författare)
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Child survival in Rwanda: Challenges and potential for improvement : Population- and hospital-based studies
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- After the 1994 genocide and collapse of the health system, Rwanda initiated major social and health reforms in order to reduce child mortality and health inequities in accordance with the Millennium Development Goals. The aim of this thesis was to assess trends in under-five mortality (U5M) and equity in child survival, to study social barriers for improved perinatal and neonatal survival, and to evaluate Helping Babies Breathe (HBB), a newborn resuscitation program.In paper I we analysed trends and social inequities in child mortality 1990−2010, using data from national Demographic and Health Surveys conducted in 2000, 2005, and 2010. The following papers were based on hospital studies in the capital of Rwanda. In paper II we explored social inequities in perinatal mortality. Using a perinatal audit approach, paper III assessed factors related to the three delays, which preceded perinatal deaths, and estimates were made of potentially avoidable deaths. Paper IV evaluated knowledge and skills gained and retained by health workers after training in HBB.Under-five mortality declined from the peak of 238 deaths per 1000 live births (95% CI 226 to 251) in 1994 to 65 deaths per 1000 live births (95% CI 61 to 70) in 2010 and concurred with decreased social gaps in child and neonatal survival between rural and urban areas and household wealth groups. Children born to women with no education still had significantly higher under-five mortality. Neonatal mortality also decreased but at a slower rate as compared to infant and U5M. Maternal rural residence or having no health insurance were linked to increased risk of perinatal death. Neither maternal education nor household wealth was associated with perinatal mortality risks. Lack of recognition of pregnancy danger signs and intrapartum-related suboptimal care were major contributors to perinatal deaths, whereof one half was estimated to be potentially avoidable. Knowledge significantly improved after training in HBB. This knowledge was sustained for at least 3 months following training whereas practical skills had declined.These results highlight the need for strengthening coverage of lifesaving interventions giving priority to underserved groups for improved child survival at community as well as at hospital levels.
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| 16. |
- Serban, Alexandra, 1988-
(författare)
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Magnetron Sputter Epitaxy of Group III-Nitride Semiconductor Nanorods
- 2017
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The III-nitride semiconductors family includes gallium nitride (GaN), aluminum nitride (AlN), indium nitride (InN), and related ternary and quaternary alloys. The research interest on this group of materials is sparked by the direct bandgaps, and excellent physical and chemical properties. Moreover, the ternary alloys (InGaN, InAlN and AlGaN) present the advantage of bandgap tuning, giving access to the whole visible spectrum, from near infrared into deep ultraviolet wavelengths. The intrinsic properties of III-nitride materials can be combined with characteristical features of nanodimension and geometry in nanorod structures. Moreover, nanorods offer the advantage of avoiding problems arising from the lack of native substrates, like lattice and thermal expansion, film – substrate mismatch.The growth and characterization of group III-nitride semiconductos nanorods, namely InAlN and GaN nanorods, is presented in this thesis. All the nanostructures were grown by employing direct-current reactive magnetron sputter epitaxy. InxAl1−xN self-assembled, core-shell nanorods on Si(111) substrates were demonstrated. A comprehensive study of temperature effect upon the morphology and composition of the nanorods was realized. The radial nanorod heterostructure consists of In-rich cores surrounded by Al-rich shells with different thicknesses. The spontaneous formation of core-shell nanorods is suggested to originate from phase separation due to spinodal decomposition. As the growth temperature increase, In desorption is favored, resulting in thicker Al-rich shells and larger nanorod diameters.Both self-assembled and selective-area grown GaN nanorods are presented. Self-assembled growth of GaN nanorods on cost-effective substrates offers a cheaper alternative and simplifies device processing. Successful growth of high- quality GaN (exhibiting strong bandedge emission and high crystalline quality) on conductive templates/substrates such as Si, SiC, TiN/Si, ZrB2/Si, ZrB2/SiC, Mo, and Ti is supported by the possibility to be used as electrodes when integrated in optoelectronic devices.The self-assembled growth leads to mainly random nucleation, resulting in nanorods with large varieties of diameters, heights and densities within a single growth run. This translates into non-uniform properties and complicates device processing. These problems can be circumvented by employing selective-area growth. Pre-patterned substrates by nano-sphere lithography resulted in GaN nanorods with controlled length, diameter, shape, and density. Well-faceted c-axis oriented GaN nanorods were grown directly onto the native SiOx layer inside nano-opening areas, exhibiting strong bandedge emission at room- temperature and single-mode lasing. Our studies on the growth mechanism revealed a different growth behavior when compared with selective-area grown GaN nanorods by MBE and MOCVD. The time-dependent growth series helped define a comprehensive growth mechanism from the initial thin wetting layer formed inside the openings, to the well-defined, uniform, hexagonal NRs resulted from the coalescence of multiple initial nuclei.
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| 17. |
- Doherty, Tanya, 1976-
(författare)
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HIV and Infant Feeding : Operational Challenges of Achieving Safe Infant Feeding Practices
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis assesses the uptake of the national Prevention of Mother to Child Transmission of HIV (PMTCT) programme in South Africa, and the challenges of achieving safe infant feeding practices in the context of HIV. The research studies contained in this thesis utilised a variety of quantitative and qualitative research methods in order to provide a full understanding of the challenges of moving from efficacy to effectiveness in PMTCT programmes. The first paper utilised a cross-sectional approach to a programme evaluation, papers two and three utilised qualitative methodologies, and paper four was based on a longitudinal cohort study design. The findings highlight the low uptake of PMTCT interventions and inappropriate infant feeding choices. The experiences of women with HIV provide an important insight into the difficulties of operationalising the WHO/UNICEF HIV and infant feeding recommendations in real life settings, where rates of HIV disclosure are low and mixed feeding is the norm. Several personal and environmental characteristics were identified that contributed to success in maintaining exclusive infant feeding practices. The research provides some guidance on the definition of appropriateness in infant feeding choices, and highlights the poor outcomes associated with formula feeding under unsafe conditions. Modifying infant feeding practices is essential in order to reduce postnatal HIV transmission and improve child survival. Interventions to improve infant feeding need to include improving the quality of counselling and support provided by health workers, with more structured assessments used to guide infant feeding choices. Efforts are also needed at the community level to increase rates of disclosure and to promote exclusive infant feeding as a norm.
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| 18. |
- Eneroth, Hanna
(författare)
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Infant Anemia and Micronutrient Status : Studies of Early Determinants in Rural Bangladesh
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Anemia and micronutrient deficiencies in infancy are common in low-income settings. These are partly due to maternal malnutrition and may impair child health and development. We studied the impact of maternal food and micronutrient supplementation, duration of exclusive breastfeeding (EBF), growth and infection on infant anemia and micronutrient status. In the MINIMat trial in Matlab, Bangladesh, pregnant women were randomized to Early or Usual promotion of enrolment in a food supplementation program and to one of three daily micronutrient supplements. Capsules containing 400µg folic acid and (a) 30 mg iron (Fe30Fol), (b) 60 mg iron (Fe60Fol), (c) 30 mg iron and other micronutrients (MMS) were provided from week 14 of gestation. Capsule intake was assessed with the eDEM device recording supplement container openings. Blood samples (n=2377) from women at week 14 and 30 were analyzed for hemoglobin (Hb). Duration of EBF and infant morbidity was based on monthly maternal recalls. Infants were weighed and measured monthly. Blood samples (n=1066) from 6-months-old infants were analyzed for Hb and plasma ferritin, zinc, retinol, vitamin B12 and folate. In women, Hb increase per capsule reached a plateau at 60 Fe60Fol capsules, indicating that nine weeks of daily supplementation produced maximum Hb response. Anemia was common (36%) at capsule intakes >60 indicating other causes of anemia than iron deficiency. In infants, vitamin B12 deficiency prevalence was lower in the MMS (26.1%) than in the Fe30Fol group (36.5%), (p=0.003) and zinc deficiency prevalence was lower in the Usual than in the Early group. There were no other differential effects of food or micronutrient supplementation on infant anemia or micronutrient status. Infants exclusively breast-fed for 4-6 months had a higher mean plasma zinc concentration (9.9±2.3 µmol/L) than infants exclusively breast-fed for <4 months (9.5±2.0 µmol/L), (p< 0.01). No other differences in anemia, iron or zinc status were observed between EBF categories. Infection, low birth weight and iron deficiency were independent risk factors for infant anemia. Regardless of studied interventions, prevalence of anemia (43%), deficiency of zinc (56%), vitamin B12, vitamin A (19%) and iron (22%) in infancy was high and further preventive strategies are needed.
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| 19. |
- Lundqvist, Martina, 1986-
(författare)
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Health Technology Assessment of Assistance Dogs and Dog-Assisted Interventions
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Dogs as an assistive aid for people with disabilities date as far back in time as the first century CE. Today, dogs are used in various settings to help and assist humans. ‘Assistance dogs’ is an umbrella term for guide dogs, hearing dogs and service dogs. They are custom trained to help and support their owners in their everyday life and thereby give them greater independence. Dogs who perform dog-assisted interventions are another type of working dog, where the dog and the owner work together as a team visiting people with various needs in different settings such as hospitals and nursing homes. These visits aim to strengthen people’s inner motivation, using the dog as an external motivator. There is a lack of evaluations of working dogs in the health technology assessment context, and in the health economic evaluation context. Hence, there is a need for structured analyses that include both the short and long-term effects and the costs of assistance dogs and dog-assisted interventions.The overall aim of this thesis is to explore and assess the use of assistance dogs and dog-assisted interventions.The research questions were investigated using a variety of methods. In paper I, inferential statistical analysis was used to analyse patient-reported outcomes measures. In paper II, a thematic content analysis was employed to explore the experiences of service and hearing dogs. To study the long-term cost-effectiveness of physical service dogs and diabetes alert dogs, a decision analytic model was used in paper III. The input data in studies I, II, and III was obtained from the Service and Hearing Dog Project. In paper III, the data was also supplemented with information from published literature and expert opinions. Paper IV investigated the effects and cost-effectiveness of dog-assisted interventions, and takes the form of a systematic review.Paper I showed that a service or hearing dog may have positive impact on its owner’s health-related quality of life, well-being and activity level. Paper II showed that owners of service or hearing dogs experienced both positive physical and psychosocial effects from their dog. Negative experiences were also identified, for example being denied access to public places and negative attitudes from other people. Paper III showed that physical service dogs and diabetes alert dogs are cost-effective in comparison with regular companion dogs, resulting in both lower costs and a gain in QALYs. The one-way sensitivity analysis did not change the results, but the probabilistic sensitivity analysis showed that the results were uncertain. Synthesizing the results from the review in paper IV showed that dog-assisted interventions for therapeutic purposes led to minor to moderate effects in psychiatric conditions. Dog-assisted interventions as an activity had minor to moderate effects on cognitive disorders, and dog-assisted interventions for support purposes were beneficial in different types of medical interventions. Studies of cost-effectiveness were lacking. To conclude, assistance dogs are valuable and may be cost-effective for use as assistive aids and dog-assisted interventions render minor to moderate effects in certain situations in healthcare settings.
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| 20. |
- Nga, Nguyen Thu, 1955-
(författare)
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Neonatal Mortality in Vietnam : Challenges and Effects of a Community-Based Participatory Intervention
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Globally neonatal mortality accounts for 40% of under-five deaths. Participatory interventions where the local problems are addressed have been successful in some settings.The aim of this thesis was to describe challenges in perinatal health in a Vietnamese province, and to evaluate the effect of a facilitated intervention with local stakeholder groups that used a problem-solving approach to neonatal survival during three years.The NeoKIP trial (Neonatal Knowledge Into Practice, ISRCTN44599712) had a cluster-randomized design (44 intervention communes, 46 control). Laywomen facilitated Maternal-and-Newborn Health Groups (MNHGs) and used Plan-Do-Study-Act cycles to address perinatal health problems. Births and neonatal deaths were monitored. Interviews were performed in households of neonatal deaths and randomly selected live births. Use of health services was mapped. The primary healthcare staff’s knowledge on newborn care was assessed before and after the intervention.Neonatal mortality rate (NMR) was 16/1000 live births (variation 10 - 44/1000 between districts). Home deliveries accounted for one fifth of neonatal deaths, and health facilities with least deliveries had higher NMR. Main causes of death were prematurity/low birth-weight (37.8 %), intrapartum-related deaths (33.2 %) and infections (13.0 %). Annual NMR was 19.1, 19.0 and 11.6/1000 live births in intervention communes (18.0, 15.9 and 21.1 in control communes); adjusted OR 1.08 [0.66-1.77], 1.23 [0.75-2.01], and 0.51 [0.30-0.89], respectively. Women in intervention communes more frequently attended antenatal care, prepared for delivery and gave birth at institutions. Primary healthcare staff’s knowledge on newborn care increased slightly in intervention communes.This model of facilitation of local stakeholder groups using a perinatal problem-solving approach was successful and may be feasible to scale-up in other settings.
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| 21. |
- Norlin, Jenny, 1982-
(författare)
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Effectiveness and costs of new medical technologies : register-based research in psoriasis
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Psoriasis is a chronic, immunological and systemic disease with an estimated prevalence of about 2-3 percent. Psoriasis is associated with the joint disease psoriasis arthropathy. There are several treatments options available for psoriasis and patients with moderate to severe psoriasis generally need systemic agents. In 2004 biologics were introduced for patients with moderate to severe psoriasis in Sweden.The overall objective of this thesis was to assess the relationship between Health Related Quality of Life (HRQOL) and clinical outcome measures in psoriasis patients, to analyse the effectiveness of biologics in psoriasis in everyday clinical practice and to explore how costs of the psoriasis population changed after the introduction of biologics in Sweden.Methods: Research was based on national administrative registers and PsoReg, the Swedish registry for systemic treatment of psoriasis. In a cross-sectional study (paper I) the three outcome measures: the generic HRQOL measure EQ-5D, the dermatology specific HRQOL measure the Dermatology Life Quality Index (DLQI) and the clinical measure of skin involvement, Psoriasis Area and Severity Index (PASI), were analysed by demographic characteristics. The generic EQ-5D among psoriasis patients was compared to previously published values for the general population in Sweden. Relationships between measures were examined with correlation tests and regression analysis. A longitudinal study included patients registered in PsoReg who switched to a biologic agent for the first time during registration (paper II). The three outcomes EQ-5D, DLQI, and PASI were analysed before and after switch in the overall patient group and in subgroups. The relative effectiveness of continuing with the standard care of conventional treatment compared to switching from standard care to biologics was analysed in patients with moderate to severe psoriasis (paper III). Patients in PsoReg were matched with propensity scores and average treatment effects were estimated. The estimated outcomes were the change of EQ-5D, DLQI, and PASI. Patients were identified in national registers at the National Board of Health and Welfare when analysing costs; either by a registration of a psoriasis diagnosis in the national patients register and/or by a registration in the prescribed drugs register of a topical treatment with calcipotriol, a substance which has the indication psoriasis only (paper IV). Direct costs included patients’ visits in specialist health care and prescribed drugs used for psoriasis treatment, retrieved from the national patients register and the prescribed drugs register, respectively. Indirect costs included productivity loss in terms of sick leave and disability pension, which estimated as excess costs compared to controls. Controls were selected from the normal population and matched on sex, age and municipality. Productivity loss was estimated based on data from the Longitudinal integration database for health insurance and labour market studies at Statistics Sweden.Results: Patients with moderate to severe psoriasis had significantly lower HRQOL in EQ-5D than the general population (paper I). Women rated their HRQOL lower than men, even though men had more severe clinical skin involvement than women. (paper I). The generic measure EQ-5D and the dermatology-specific DLQI had moderate correlations whereas EQ-5D had low correlation with the clinical measure PASI (paper I). Patients who switched to a biologic agent during registration in PsoReg had significant improvements in all outcomes (paper II). Patients who fulfilled the criteria for moderate to severe psoriasis had the highest benefits of the biologic agents (paper II). The matched conventionally and biologically treated patients with moderate to severe psoriasis were essentially equal in important observable variables (paper III). The subgroup of patients not responding to conventional treatment had high potential benefits of biologic agents (paper III). Individuals with psoriasis had sick leave and disability pension to a larger extent than their matched controls (paper IV). Direct costs increased, whereas the indirect costs of productivity loss decreased between 2006 and 2009 (paper IV).Conclusion: Psoriasis is associated both with direct costs and indirect costs, and it has a negative impact on patients’ HRQOL. When evaluating psoriasis treatments and making decisions about treatment guidelines, both generic, dermatology-specific HRQOL measures, and clinical measures are necessary; as they answer to different needs. Although dependent on data quality, generalisability, and current pricing, results suggest that conventional treatments are suitable as first line and biologic agents as second line treatment. Results indicate that the different types of systemic treatments are not allocated optimally among patients with psoriasis in Swedish clinical practice.
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| 22. |
- Serban, Alexandra, 1988-, et al.
(författare)
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Magnetron Sputter Epitaxy of High-Quality GaN Nanorods on Functional and Cost-Effective Templates/Substrates
- 2017
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Ingår i: Energies. - Basel, Switzerland : MDPI AG. - 1996-1073. ; 10:9
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate the versatility of magnetron sputter epitaxy by achieving high-quality GaN nanorods on different substrate/template combinations, specifically Si, SiC, TiN/Si, ZrB2/Si, ZrB2/SiC, Mo, and Ti. Growth temperature was optimized on Si, TiN/Si, and ZrB2/Si, resulting in increased nanorod aspect ratio with temperature. All nanorods exhibit high purity and quality, proved by the strong bandedge emission recorded with cathodoluminescence spectroscopy at room temperature as well as transmission electron microscopy. These substrates/templates are affordable compared to many conventional substrates, and the direct deposition onto them eliminates cumbersome post-processing steps in device fabrication. Thus, magnetron sputter epitaxy offers an attractive alternative for simple and affordable fabrication in optoelectronic device technology.
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| 23. |
- Serban, Elena Alexandra, 1988-, et al.
(författare)
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Site-controlled growth of GaN nanorod arrays by magnetron sputter epitaxy
- 2018
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Ingår i: Thin Solid Films. - : Elsevier. - 0040-6090 .- 1879-2731. ; 660, s. 950-955
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Tidskriftsartikel (refereegranskat)abstract
- Catalyst-free GaN nanorod regular arrays have been realized by reactive magnetron sputter epitaxy. Two nanolithographic methods, nanosphere lithography (NSL) and focused ion beam lithography (FIBL), were applied to pattern Si substrates with TiNx masks. The growth temperature was optimized for achieving selectivity and well-faceted nanorods grown onto the NSL-patterned substrates. With increasing temperature from 875 to 985 °C, we observe different growth behaviors and associate them with selective insensitive, diffusion-dominated, and desorption-dominated zones. To further achieve site-specific and diameter control, these growth parameters were transferred onto FIBL-patterned substrates. Further investigation into the FIBL process through tailoring of milling current and time in combination with varying nanorod growth temperature, suggests that minimization of mask and substrate damage is the key to attain uniform, well-defined, single, and straight nanorods. Destruction of the mask results in selective area growth failure, while damage of the substrate surface promotes inclined nanorods grown into the openings, owning to random oriented nucleation.
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