Self-assembling nanoscale systems

Self-assembly is ubiquitous in different areas of science, for example in crystals and viruses, and also plays crucial roles in nanotechnology. Many commonalities link these self-assembling systems, in spite of their complexity and different length and time scales. In this thesis, we take an interdisciplinary perspective to gain new insights into self-assembly, exploring ways of modelling self-assembling systems that are relevant across these different fields. A challenge in nanotechnology is to develop self-assembling systems capable of generating a desired outcome. An example is graphene nanoribbons, which are a novel type of semiconductor material with great potential in the nanotech industry. In this context, it is unclear which strategies are best for controlling the output of a self-assembly process, either by manipulation of the thermodynamic environment of the assembling system, or other methods of directing self-assembly. We use quantitative modelling of the kinetics of self-assembly as a tool to predict experimental results in self-assembling systems that are too complex for detailed experimental investigation. Self-assembly of viral protein shells is an example from biology. Viruses have evolved niche methods of assembly that are both robust and highly efficient, as the virus mutation rates are very high, especially in RNA viruses. The viruses discussed in this thesis have an added layer of complexity; it is thought that sequence-specific interactions between viral genomes and the protein building blocks of the viral capsids have a strong impact on the assembly process. We have developed here novel analysis techniques for the modelling of this co-assembly scenario. We use these mechanistic insights to develop new theoretical tools to analyse structural data, providing unprecedented insights into the asymmetric organization of the packaged genome

A group theoretical approach to structural transitions of icosahedral quasicrystals and point arrays

In this paper we describe a group theoretical approach to the study of structural transitions of icosahedral quasicrystals and point arrays. We apply the concept of Schur rotations, originally proposed by Kramer, to the case of aperiodic structures with icosahedral symmetry; these rotations induce a rotation of the physical and orthogonal spaces invariant under the icosahedral group, and hence, via the cut-and-project method, a continuous transformation of the corresponding model sets. We prove that this approach allows for a characterisation of such transitions in a purely group theoretical framework, and provide explicit computations and specific examples. Moreover, we prove that this approach can be used in the case of finite point sets with icosahedral symmetry, which have a wide range of applications in carbon chemistry (fullerenes) and biology (viral capsids).Peer reviewe

Moving towards effective therapeutic strategies for Neuronal Ceroid Lipofuscinosis.

The Neuronal Ceroid Lipofuscinoses (NCLs) are a family of autosomal recessive neurodegenerative disorders that annually affect 1:100,000 live births worldwide. This family of diseases results from mutations in one of 14 different genes that share common clinical and pathological etiologies. Clinically, the diseases are subcategorized into infantile, late-infantile, juvenile and adult forms based on their age of onset. Though the disease phenotypes may vary in their age and order of presentation, all typically include progressive visual deterioration and blindness, cognitive impairment, motor deficits and seizures. Pathological hallmarks of NCLs include the accumulation of storage material or ceroid in the lysosome, progressive neuronal degeneration and massive glial activation. Advances have been made in genetic diagnosis and counseling for families. However, comprehensive treatment programs that delay or halt disease progression have been elusive. Current disease management is primarily targeted at controlling the symptoms rather than curing the disease. Recognizing the growing need for transparency and synergistic efforts to move the field forward, this review will provide an overview of the therapeutic approaches currently being pursued in preclinical and clinical trials to treat different forms of NCL as well as provide insight to novel therapeutic approaches in development for the NCLs

Molecular interactions of FG nucleoporin repeats at high resolution

Proteins that contain repeat phenylalanine-glycine (FG) residues phase separate into oncogenic transcription factor condensates in malignant leukaemias, form the permeability barrier of the nuclear pore complex and mislocalize in neurodegenerative diseases. Insights into the molecular interactions of FG-repeat nucleoporins have, however, remained largely elusive. Using a combination of NMR spectroscopy and cryoelectron microscopy, we have identified uniformly spaced segments of transient β-structure and a stable preformed α-helix recognized by messenger RNA export factors in the FG-repeat domain of human nucleoporin 98 (Nup98). In addition, we have determined at high resolution the molecular organization of reversible FG–FG interactions in amyloid fibrils formed by a highly aggregation-prone segment in Nup98. We have further demonstrated that amyloid-like aggregates of the FG-repeat domain of Nup98 have low stability and are reversible. Our results provide critical insights into the molecular interactions underlying the self-association and phase separation of FG-repeat nucleoporins in physiological and pathological cell activities

The bidirectional longitudinal association between depressive symptoms and HbA 1c : a systematic review and meta‐analysis

Aim To investigate whether there is a bidirectional longitudinal association of depression with HbA1c. Methods We conducted a systematic literature search in PubMed, PsycINFO, CINAHL and EMBASE for observational, longitudinal studies published from January 2000 to September 2020, assessing the association between depression and HbA1c in adults. We assessed study quality with the Newcastle-Ottawa-Scale. Pooled effect estimates were reported as partial correlation coefficients (rp) or odds ratios (OR). Results We retrieved 1,642 studies; 26 studies were included in the systematic review and eleven in the meta-analysis. Most studies (16/26) focused on type 2 diabetes. Study quality was rated as good (n=19), fair (n=2) and poor (n=5). Of the meta-analysed studies, six investigated the longitudinal association between self-reported depressive symptoms and HbA1c and five the reverse longitudinal association, with a combined sample size of n=48,793 and a mean follow-up of 2 years. Higher levels of baseline depressive symptoms were associated with subsequent higher levels of HbA1c (partial r=0.07;[95%CI0.03,0.12]; I238%). Higher baseline HbA1c values were also associated with 18% increased risk of (probable) depression (OR=1.18;[95%CI1.12,1.25]; I20.0%). Conclusions Our findings support a bidirectional longitudinal association between depressive symptoms and HbA1c. However, the observed effect sizes were small and future research in large-scale longitudinal studies is needed to confirm this association. Future studies should investigate the role of type of diabetes and depression, diabetes distress and diabetes self-management behaviours. Our results may have clinical implications, as depressive symptoms and HbA1c levels could be targeted concurrently in the prevention and treatment of diabetes and depression

Adipokine Imbalance in the Pericardial Cavity of Cardiac and Vascular Disease Patients

Aim Obesity and especially hypertrophy of epicardial adipose tissue accelerate coronary atherogenesis. We aimed at comparing levels of inflammatory and atherogenic hormones from adipose tissue in the pericardial fluid and circulation of cardiovascular disease patients. Methods and Results Venous plasma (P) and pericardial fluid (PF) were obtained from elective cardiothoracic surgery patients (n = 37). Concentrations of leptin, adipocyte fatty acid-binding protein (AFABP) and adiponectin (APN) were determined by enzyme-linked immunosorbent assays (ELISA). The median concentration of leptin in PF (4.3 (interquartile range: 2.8-9.1) mu g/L) was comparable to that in P (5.9 (2.2-11) mu g/L) and these were significantly correlated to most of the same patient characteristics. The concentration of A-FABP was markedly higher (73 (28-124) versus 8.4 (5.2-14) mu g/L) and that of APN was markedly lower (2.8 (1.7-4.2) versus 13 (7.2-19) mg/L) in PF compared to P. APN in PF was unlike in P not significantly related to age, body mass index, plasma triglycerides or coronary artery disease. PF levels of APN, but not A-FABP, were related to the size of paracardial adipocytes. PF levels of APN and A-FABP were not related to the immunoreactivity of paracardial adipocytes for these proteins. Conclusion In cardiac and vascular disease patients, PF is enriched in A-FABP and poor in APN. This adipokine microenvironment is more likely determined by the heart than by the circulation or paracardial adipose tissue.published_or_final_versio

Virtual reality-based cognitive behavioural therapy for patients with generalized social anxiety disorder:a pilot study

BACKGROUND: Patients with generalized social anxiety disorder (SAD) avoid various social situations and can be reluctant to engage in in vivo exposure therapy. Highly personalized practising can be required before patients are ready to perform in vivo exposure. Virtual reality-based therapy could be beneficial for this group. AIMS: To assess the feasibility and potential effect of virtual reality-based cognitive behavioural therapy (VR-CBT) for patients with severe generalized SAD. METHODS: Fifteen patients with generalized SAD attended up to 16 VR-CBT sessions. Questionnaires on clinical and functional outcomes, and diary assessments on social activity, social anxiety and paranoia were completed at baseline, post-treatment and at 6-months follow-up. RESULTS: Two patients dropped out of treatment. Improvements in social anxiety and quality of life were found at post-treatment. At follow-up, depressive symptoms had decreased, and the effect on social anxiety was maintained. With respect to diary assessments, social anxiety in company and paranoia were significantly reduced by post-treatment. These improvements were maintained at follow-up. No increase was observed in social activity. CONCLUSIONS: This uncontrolled pilot study demonstrates the feasibility and treatment potential of VR-CBT in a difficult-to-treat group of patients with generalized SAD. Results suggest that VR-CBT may be effective in reducing anxiety as well as depression, and can increase quality of life

Comparison of the Analytical and Clinical Performance of Five Tests for the Detection of Human Papillomavirus Genital Infection

HPV-based screening provides greater protection against cervical cancer (CC) than cytology-based strategies. Currently, several molecular diagnostic assays for the detection of human papillomavirus (HPV) are available. In this study, we analyzed 5 different HPV testing and genotyping techniques (Hybrid Capture 2 [HC2; Qiagen, Hilden, Germany], AnyplexTMII HPV28 [Anyplex; Seegene, Seoul, Korea], Linear Array [Roche, Branchburg, NJ, USA], GP5+/6+ PCR-EIA-RH [Labo Bio-medical Products, Rijswijk, The Netherlands] and CLART2 [Genomica, Madrid, Spain]) in 295 women referred to the hospital Colposcopy Clinic from 2007 to 2008 due to positive HPV test results or an abnormal Pap test. DNA extraction for HPV genotyping was performed in cervical sample specimens after Pap test and HPV detection by HC2. The inclusion criteria were: (1) adequate cervical sampling with sufficient material for the Pap test and HPV detection and genotyping, and (2) colposcopically-directed biopsy and/or endocervical curettage. HC2 showed the highest sensitivity for high-grade squamous intraepithelial lesion and CC (HSIL+) detection (96.1%), but all the HPV genotyping tests showed a higher specificity. (Anyplex 86.8%; Linear Array 86.0%; GP5+/6+ 78.8%; CLART2 76.5%). The agreement between HC2 results and the other techniques was similar: 82.4%, kappa=0.650 for Anyplex; 83.4%, kappa=0.670 for Linear Array, 79.93%, kappa=0.609 for GP5+/6+ and 82.4%, kappa=0.654 for CLART2. HPV 16 and/or 18 infection was a risk factor for underlying HSIL+ in the univariate analysis. Anyplex showed the highest risk of underlying HSIL+ after positive HPV 16 and/or 18 tests (OR 31.1; 95% IC 12.1-80.0)

Searching for Novel Biomarkers Using a Mouse Model of CLN3-Batten Disease

CLN3-Batten disease is a rare, autosomal recessive disorder involving seizures, visual, motor and cognitive decline, and premature death. The Cln3Δex7/8 mouse model recapitulates several phenotypic characteristics of the most common 1.02kb disease-associated deletion. Identification of reproducible biomarker(s) to facilitate longitudinal monitoring of disease progression and provide readouts for therapeutic response has remained elusive. One factor that has complicated the identification of suitable biomarkers in this mouse model has been that variations in animal husbandry appear to significantly influence readouts. In the current study, we cross-compared a number of biological parameters in blood from Cln3Δex7/8 mice and control, non-disease mice on the same genetic background from multiple animal facilities in an attempt to better define a surrogate marker of CLN3-Batten disease. Interestingly, we found that significant differences between Batten and non-disease mice found at one site were generally not maintained across different facilities. Our results suggest that colony variation in the Cln3Δex7/8 mouse model of CLN3-Batten disease can influence potential biomarkers of the disease