Opin vísindi

 

Nýlega bætt við

Verk
Heterologous and homologous prime-boost immunization strategies to enhance immune responses in early life
(University of Iceland, School of Health Sciences, Faculty of Medicine, 2026-09-14) Foroutan Pajoohian, Poorya; Stefanía Bjarnarsson; Ingileif Jónsdóttir; Faculty of Medicine (UI); Læknadeild (HÍ); School of Health Sciences (UI); Heilbrigðisvísindasvið (HÍ)
In early life the immune system is characterized by generation of weaker and less durable vaccine-induced antibody responses than in adulthood. This poses a major challenge for the development of vaccines targeting pathogens that require that both strong systemic and mucosal immune responses are elicited to achieve protective immunity. The overall aim of this thesis project was to determine how heterologous prime-boost immunization routes in comparison with the conventional parenteral homologous immunization shape early life humoral immunity to a pneumococcal conjugate vaccine, Pn1-CRM197, and to develop and characterize immunization strategies capable of improving both systemic and mucosal responses in early life. A neonatal mouse model was used in the study. Mice were immunized with Pn1-CRM197 formulated with the adjuvants CAF01 or mmCT for subcutaneous or intranasal administration, respectively. Across this PhD study, vaccine-specific IgG and IgA antibody responses, antibody-secreting cells, germinal center activity, T follicular helper and T follicular regulatory cells, memory B cell generation, plasmablast/plasma cell differentiation and their expression of the survival and activation receptors BAFF-R, TACI and BCMA were examined in spleen, cervical and inguinal lymph nodes and bone marrow. Immunization schedules that included a mucosal administration enhanced vaccinespecific IgA responses in serum and mucosal compartments compared with homologous subcutaneous immunization. However, heterologous subcutaneous priming followed by intranasal booster, while improving mucosal output and generating combined systemic–mucosal responses, did not induce systemic IgG responses comparable to homologous subcutaneous/subcutaneous immunization. Our results showed that the routes of immunizations determined the anatomical site of germinal center induction and shaped the germinal center output. Homologous subcutaneous/subcutaneous immunization preferentially induced germinal center responses in spleen and inguinal lymph nodes, promoted plasmablast/plasma cell differentiation in spleen, increased expression of the survival receptor BCMA on plasma cells in inguinal lymph nodes and yielded high systemic IgG responses. In contrast, heterologous subcutaneous/intranasal immunization redirected the induction of plasmablast/plasma cells responses, BCMA expression toward cervical lymph nodes and favoured the generation of IgM⁺ germinal center-derived memory B cells in all lymphoid organs assessed, and with enhanced BAFF-R and TACI expression, receptor crucial for survival and re-activation, together with stronger IgA responses. The major finding of my study was that reversal of the heterologous immunization schedule, consisting of intranasal priming and subcutaneous booster, successfully overcame the main limitation of the heterologous immunization schedule. It preserved the mucosal advantage of intranasal immunization while inducing systemic IgG responses comparable to homologous subcutaneous/subcutaneous immunization, alongside enhanced serum and salivary IgA responses, increased bone marrow homing of BCMA⁺ plasmablasts/plasma cells, expanded memory B cell output but maintained the favoured generation of IgM⁺ germinal center-derived memory B cells in all lymphoid organs. Together, these studies demonstrate that in early life, the route and order of primeboost immunization affect not only the magnitude, but also the localization and quality of humoral immunity. Among the immunization strategies tested, intranasal priming followed by subcutaneous booster emerged as the most suitable approach, combining robust systemic immunity and mucosal responses, enhanced bone marrow homing of BCMA⁺ plasmablasts/plasma cells and expanded memory B cell output. These findings provide a framework for the rational design of early life vaccination strategies against respiratory pathogens.
Verk
Anxiety and Distress Tolerance as Mediators between Complex Posttraumatic Stress Disorder Symptoms and Gambling Severity in Veterans
(2026-03) Dighton, Glen; Whiteford, Seb; Quigley, Martyn; Dymond, Simon; Department of Psychology
Experiences of gambling-related harm are significant concerns among military veterans, particularly those with posttraumatic stress disorder (PTSD) and complex PTSD (CPTSD). CPTSD, as outlined in the ICD-11, includes disturbances in self-organisation (DSO), encompassing affective dysregulation, negative self-concept, and interpersonal difficulties. While anxiety and distress tolerance (DT) have been implicated in PTSD-related maladaptive behaviours, their roles in the relationship between CPTSD and gambling risk severity remain unclear. This study examines whether anxiety and DT mediate the association between CPTSD symptom clusters (PTSD and DSO) and gambling severity in UK Armed Forces veterans. A cross-sectional study was conducted with UK ex-service personnel (n = 346) who completed the International Trauma Questionnaire for CPTSD, the Generalised Anxiety Disorder scale, the Distress Tolerance Scale, and the Problem Gambling Severity Index. Mediation analyses were conducted using bootstrapped regression models. Anxiety was found to be a significant indirect pathway between CPTSD symptoms and gambling risk severity, with a stronger indirect effect observed for DSO symptoms than PTSD-specific symptoms. In contrast, DT did not show a significant indirect pathway, indicating that deficits in DT may not be central to gambling behaviours in veterans with CPTSD. These findings highlight the critical role of anxiety in gambling-related harm among veterans with symptoms of CPTSD, suggesting that interventions targeting anxiety regulation may be beneficial than those targeting distress tolerance in reducing gambling risk severity. Future research should explore additional potential pathways, such as impulsivity and trauma-related dissociation to further clarify associations between CPTSD and gambling severity.
Verk
A Dual-Functional Frequency-Selective Polarization Converting Metasurface With Reduced Backward-Scattering Characteristics
(2026) Nasir, Muhammad; Koziel, Slawomir; Pietrenko-Dabrowska, Anna; Department of Engineering
A novel dual-functional frequency-selective metasurface (MS) with low backscattering is proposed by integrating a reflective cross-polarization (LRCP) converter with a bandpass frequency-selective surface (BP-FSS). The proposed MS comprises three layers, with a cross-dipole FSS in the middle layer that provides high-efficiency bandpass transmission. The thickness, inter-gap, and interlayer spacing of the diagonally oriented metallic strip gratings (MSGs), printed on the top and bottom layers, are meticulously optimized to achieve efficient LRCP conversion while maintaining high transmittance transparency for the out-of-band frequencies. The proposed MS simultaneously exhibits two independent functionalities: co-polarized bandpass transmission from 3.74 to 5.12 GHz with a simulated insertion loss of above -1 dB, and LRCP conversion from 5.72 to 7.33 GHz with a polarization conversion ratio (PCR) exceeding 0.99. The design concept is validated using two equivalent circuit models (ECMs) corresponding to the BP-FSS and the cascaded MS configuration, as well as through measurements of the fabricated prototype comprising 16× 16 unit-cell arrays arranged in a chessboard configuration. Both the ECM predictions and measurements show good alignment with the full-wave simulation findings. In addition, the measurement results showcase significant radar cross-section (RCS) reduction across the frequency range from 5.94 - 7.21 GHz. Unlike conventional LRCP-MSs, the proposed work eliminates the need for a complete ground plane, and hence, its dual functionality makes it a promising candidate for Radome and communication platforms.
Verk
“Outcomes of treatment for people with type 2 diabetes within two nurse-led clinics in primary care in Iceland”
(2025) Birgisdóttir, Matthildur; Skúladóttir, Hafdís; Sigurðardóttir, Árún Kristín; Faculty of Nursing
As the prevalence of type 2 diabetes increases in Iceland, more nurse-led diabetes clinics have been established in primary health. This study aimed to evaluate treatment outcomes in patients with type 2 diabetes at two rural nurse-led diabetes clinics and compare these outcomes with guidelines. A retrospective cohort study was conducted in primary care settings in Northern Iceland using secondary data from medical recording systems. The sample (n = 88) included patients with two glycated haemoglobin (HbA1c) measurements taken at least 6 months apart (Time 1 and 2). Between Time 1 and 2, HbA1c levels (p = 0.049), body mass index (p = 0.013), and systolic blood pressure (p = 0.040) decreased. At time 2, approximately 70% of patients reached clinical goals for HbA1c levels, 33% for body mass index, 56% for systolic blood pressure, and 49% for diastolic blood pressure. This finding is consistent with those of other European studies in diabetes care. Assessing healthcare outcomes is beneficial for small rural clinics, where work is often conducted in isolation. This programme evaluation study conducted in two nurse-led clinics in Iceland demonstrated improved diabetes outcomes with care aligned with clinical guidelines and provided a baseline for measuring future outcomes.
Verk
Public Perceptions of Gambling in the UK Armed Forces : Understanding Stigma Via a Vignette Experiment
(2026-03) Smith, Jessica; Dymond, Simon; Torrance, Jamie; Department of Psychology
Gambling-related harm among armed forces (AF) personnel is a growing concern, yet public perceptions remain underexplored. Anticipated public stigma (the fear of how others perceive you) of gambling among the AF is a potential barrier to help-seeking. Understanding how the public perceives gambling in the AF is essential for shaping stigma-reduction strategies. A randomised, online 2 × 2 between-subjects experiment was conducted. A representative sample of the United Kingdom public (N = 396) was recruited through Prolific and randomly assigned to view a vignette featuring either an AF member or non-AF civilian who was described as engaging in either harmful or non-harmful gambling. Following exposure to their assigned vignette, participants completed measures assessing stigma and empathy towards the depicted individual. Participants perceived individuals from the AF as significantly more dangerous (p =.002) compared to non-AF civilians. When the vignette depicted gambling-related harm, as opposed to recreational gambling, participants reported significantly higher stigma across seven of the ten stigma measures (all p <.001). This study highlights how public stigma towards gambling harm is strong and can be shaped by military status, with AF personnel facing increased perceptions of dangerousness. Findings underscore the need for public stigma-reduction strategies that address both gambling-related and military-specific misconceptions.

Flokkar í Opnum vísindum

Veldu flokk til að skoða.

Niðurstöður 1 - 9 af 9

Öll gögn í Opnum vísindum eru vernduð af ákvæðum höfundalaga og með öllum réttindum áskildum, nema annað sé tekið fram.