152 research outputs found
Enhancing Compressed Sensing 4D Photoacoustic Tomography by Simultaneous Motion Estimation
A crucial limitation of current high-resolution 3D photoacoustic tomography (PAT) devices that
employ sequential scanning is their long acquisition time. In previous work, we demonstrated how
to use compressed sensing techniques to improve upon this: images with good spatial resolution and
contrast can be obtained from suitably subsampled PAT data acquired by novel acoustic scanning
systems if sparsity-constrained image reconstruction techniques such as total variation regularization
are used. Now, we show how a further increase of image quality can be achieved for imaging
dynamic processes in living tissue (4D PAT). The key idea is to exploit the additional temporal
redundancy of the data by coupling the previously used spatial image reconstruction models with
sparsity-constrained motion estimation models. While simulated data from a 2D numerical phantom
will be used to illustrate the main properties of this recently developed joint-image-reconstructionand-motion-estimation framework, measured data from a dynamic experimental phantom will also
be used to demonstrate its potential for challenging, large-scale, real-world, 3D scenarios. The
latter only becomes feasible if a carefully designed combination of tailored optimization schemes is
employed, which we describe and examine in more detail
Clinical utility of a nested nucleic acid amplification format in comparison to viral culture for the diagnosis of mucosal herpes simplex infection in a genitourinary medicine setting
BACKGROUND: Nested nucleic acid amplification tests are often thought too sensitive or prone to generatingfalse positive results for routine use. The current study investigated the specificity and clinicalutility of a routine multiplex nested assay for mucosal herpetic infections. METHODS: Ninety patients, categorised into those clinically diagnosed to (a) have and (b) not haveherpetic infection, were enrolled. Swabs from oral and ano-genital sites were assayed by thenested assay and culture and the results assessed against clinical evaluation for diagnosingherpetic infections; cell content was also recorded. RESULTS: Twenty-six and 64 patients were thought to (a) have and (b) not have mucosal herpeticinfection. Taking the clinical evaluation as indicating the presence of herpetic infection, thenested polymerase chain reaction and culture had respective sensitivities of 19/26 (73%) and12/26 (46%) (Χ(2) p = 0.02). There was no significant difference in specificities between nPCR62/64 (97%) and culture 63/64 (98%) (Χ(2) p = 1.0). Cell content was important for viraldetection by nPCR (Χ(2) p = 0.07) but not culture. Nesting was found necessary for sensitivity anddid not reduce specificity. Assay under-performance appeared related to sub-optimal cellcontent (20%) but may have reflected clinical over-diagnosis. The results suggest the need forvalidating specimen cell quality. CONCLUSIONS: This study questions the value of routine laboratory confirmation of mucosal herpetic infection. The adoption of a more discriminatory usage of laboratory diagnostic facilities for genital herpetic infection, taking account of cell content, and restricting it to those cases where it actually affects patient management, may be warranted
The continuity of effect of schizophrenia polygenic risk score and patterns of cannabis use on transdiagnostic symptom dimensions at first-episode psychosis: findings from the EU-GEI study
Diagnostic categories do not completely reflect the heterogeneous expression of psychosis. Using data from the EU-GEI study, we evaluated the impact of schizophrenia polygenic risk score (SZ-PRS) and patterns of cannabis use on the transdiagnostic expression of psychosis. We analysed first-episode psychosis patients (FEP) and controls, generating transdiagnostic dimensions of psychotic symptoms and experiences using item response bi-factor modelling. Linear regression was used to test the associations between these dimensions and SZ-PRS, as well as the combined effect of SZ-PRS and cannabis use on the dimensions of positive psychotic symptoms and experiences. We found associations between SZ-PRS and (1) both negative (B = 0.18; 95%CI 0.03â0.33) and positive (B = 0.19; 95%CI 0.03â0.35) symptom dimensions in 617 FEP patients, regardless of their categorical diagnosis; and (2) all the psychotic experience dimensions in 979 controls. We did not observe associations between SZ-PRS and the general and affective dimensions in FEP. Daily and current cannabis use were associated with the positive dimensions in FEP (B = 0.31; 95%CI 0.11â0.52) and in controls (B = 0.26; 95%CI 0.06â0.46), over and above SZ-PRS. We provide evidence that genetic liability to schizophrenia and cannabis use map onto transdiagnostic symptom dimensions, supporting the validity and utility of the dimensional representation of psychosis. In our sample, genetic liability to schizophrenia correlated with more severe psychosis presentation, and cannabis use conferred risk to positive symptomatology beyond the genetic risk. Our findings support the hypothesis that psychotic experiences in the general population have similar genetic substrates as clinical disorders
A review of non-linear structural control techniques
In this articles the authors present a review of non-linear structural control techniques. This is an area of growing importance in a range of engineering applications, where non-linear behaviour is encountered. Structural control is usually divided into three main areas: (a) passive (b) semi-active, and (c) active control. This article follows this convention, and highlights in each section the relevant state of the art for non-linear systems, with additional references to related linear approaches
The relationship between ingroup identity and Paranoid ideation among people from African and African Caribbean backgrounds.
OBJECTIVES: People from ethnic minority groups experience higher rates of paranoid delusions compared with people from ethnic majority groups. Identifying with social groups has been shown to protect against mental health symptoms; however, no studies have investigated the relationship between social identification and paranoia in ethnic minority populations. Here, we investigated the association between British identification and paranoia in a sample of people from African and African Caribbean backgrounds living in the United Kingdom. We also assessed the role of potential mediating (self-esteem and locus of control) and moderating (contact with White British people) factors. DESIGN: Cross-sectional quantitative survey design. METHODS: We recruited 335 people from African and African Caribbean backgrounds who completed online self-report measures of identification with Great Britain, self-esteem, locus of control, positive and negative contact with White British people, and paranoia. RESULTS: A parallel moderated mediation model indicated that British identification was associated with lower paranoia when participants experienced primarily positive contact with White British people. British identification was associated with higher paranoia when participants had primarily negative contact with White British people. Both effects were mediated by changes in locus of control, but self-esteem was not implicated in either pathway. CONCLUSIONS: Identification with the majority culture is associated both positively and negatively with paranoid beliefs depending on the types of social interactions people experience. The findings have implications for preventative social prescribing initiatives and for understanding the causes of the high rates of psychosis in ethnic minority populations. PRACTITIONER POINTS: People from African and African Caribbean backgrounds experience high rates of paranoia, which may stem from social causes such as lack of belonging and negative social experiences. Among people from African backgrounds living in the UK, British identification is associated with lower paranoia when people's social experiences with White British people are positive and higher paranoia when their social experiences with White British people are negative. It is recommended that social interventions designed to reduce paranoia in vulnerable groups foster positive social contact and community belonging, which should enhance feelings of personal control. Understanding the complex interplay between social identity and social contact in the development of paranoia may help therapists and researchers better understand the phenomenology and risk factors of paranoid symptomology
The relationship between genetic liability, childhood maltreatment, and IQ: findings from the EU-GEI multicentric caseâcontrol study
This study investigated if the association between childhood maltreatment and cognition among psychosis patients and community controls was partially accounted for by genetic liability for psychosis. Patients with first-episode psychosis (Nâ=â755) and unaffected controls (Nâ=â1219) from the EU-GEI study were assessed for childhood maltreatment, intelligence quotient (IQ), family history of psychosis (FH), and polygenic risk score for schizophrenia (SZ-PRS). Controlling for FH and SZ-PRS did not attenuate the association between childhood maltreatment and IQ in cases or controls. Findings suggest that these expressions of genetic liability cannot account for the lower levels of cognition found among adults maltreated in childhood
Recommended from our members
The EUropean Network of National Schizophrenia Networks Studying GeneâEnvironment Interactions (EU-GEI): Incidence and First-Episode CaseâControl Programme
Funder: FP7 Ideas: European Research Council; doi: http://dx.doi.org/10.13039/100011199; Grant(s): HEALTH-F2-2010-241909Abstract: Purpose: The EUropean Network of National Schizophrenia Networks Studying GeneâEnvironment Interactions (EU-GEI) study contains an unparalleled wealth of comprehensive data that allows for testing hypotheses about (1) variations in incidence within and between countries, including by urbanicity and minority ethnic groups; and (2) the role of multiple environmental and genetic risk factors, and their interactions, in the development of psychotic disorders. Methods: Between 2010 and 2015, we identified 2774 incident cases of psychotic disorders during 12.9 million person-years at risk, across 17 sites in 6 countries (UK, The Netherlands, France, Spain, Italy, and Brazil). Of the 2774 incident cases, 1130 cases were assessed in detail and form the case sample for caseâcontrol analyses. Across all sites, 1497 controls were recruited and assessed. We collected data on an extensive range of exposures and outcomes, including demographic, clinical (e.g. premorbid adjustment), social (e.g. childhood and adult adversity, cannabis use, migration, discrimination), cognitive (e.g. IQ, facial affect processing, attributional biases), and biological (DNA via blood sample/cheek swab). We describe the methodology of the study and some descriptive results, including representativeness of the cohort. Conclusions: This resource constitutes the largest and most extensive incidence and caseâcontrol study of psychosis ever conducted
Recommended from our members
The EUropean Network of National Schizophrenia Networks Studying GeneâEnvironment Interactions (EU-GEI): Incidence and First-Episode CaseâControl Programme
Funder: FP7 Ideas: European Research Council; doi: http://dx.doi.org/10.13039/100011199; Grant(s): HEALTH-F2-2010-241909Abstract: Purpose: The EUropean Network of National Schizophrenia Networks Studying GeneâEnvironment Interactions (EU-GEI) study contains an unparalleled wealth of comprehensive data that allows for testing hypotheses about (1) variations in incidence within and between countries, including by urbanicity and minority ethnic groups; and (2) the role of multiple environmental and genetic risk factors, and their interactions, in the development of psychotic disorders. Methods: Between 2010 and 2015, we identified 2774 incident cases of psychotic disorders during 12.9 million person-years at risk, across 17 sites in 6 countries (UK, The Netherlands, France, Spain, Italy, and Brazil). Of the 2774 incident cases, 1130 cases were assessed in detail and form the case sample for caseâcontrol analyses. Across all sites, 1497 controls were recruited and assessed. We collected data on an extensive range of exposures and outcomes, including demographic, clinical (e.g. premorbid adjustment), social (e.g. childhood and adult adversity, cannabis use, migration, discrimination), cognitive (e.g. IQ, facial affect processing, attributional biases), and biological (DNA via blood sample/cheek swab). We describe the methodology of the study and some descriptive results, including representativeness of the cohort. Conclusions: This resource constitutes the largest and most extensive incidence and caseâcontrol study of psychosis ever conducted
- âŠ