1,406 research outputs found

    Comparing numerical error and visual quality in reconstructions from compressed digital holograms

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    Digital holography is a well-known technique for both sensing and displaying real-world three-dimensional objects. Compression of digital holograms has been studied extensively, and the errors introduced by lossy compression are routinely evaluated in a reconstruction domain. Mean-square error predominates in the evaluation of reconstruction quality. However, it is not known how well this metric corresponds to what a viewer would regard as perceived error, nor how consistently it functions across different holograms and different viewers. In this study, we evaluate how each of seventeen viewers compared the visual quality of compressed and uncompressed holograms' reconstructions. Holograms from five different three-dimensional objects were used in the study, captured using a phase-shift digital holography setup. We applied two different lossy compression techniques to the complex-valued hologram pixels: uniform quantization, and removal and quantization of the Fourier coefficients, and used seven different compression levels with each

    Visual perception of digital holograms on autostereoscopic displays

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    In digital holography we often capture optically a 3D scene and reconstruct the perspectives numerically. The reconstructions are routinely in the form of a 2D image slice, an extended focus image, or a depth map from a single perspective. These are fundamentally 2D (or at most 2.5D) representations and for some scenes are not certain to give the human viewer a clear perception of the 3D features encoded in the hologram (occlusions are not overcome, for example). As an intermediate measure towards a full-field optoelectronic display device, we propose to digitally process the holograms to allow them to be displayed on conventional autostereoscopic displays

    Dynamics of the peripheral membrane protein P2 from human myelin measured by neutron scattering - a comparison between wild-type protein and a hinge mutant

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    Myelin protein P2 is a fatty acid-binding structural component of the myelin sheath in the peripheral nervous system, and its function is related to its membrane binding capacity. Here, the link between P2 protein dynamics and structure and function was studied using elastic incoherent neutron scattering (EINS). The P38G mutation, at the hinge between the β barrel and the α-helical lid, increased the lipid stacking capacity of human P2 in vitro, and the mutated protein was also functional in cultured cells. The P38G mutation did not change the overall structure of the protein. For a deeper insight into P2 structure-function relationships, information on protein dynamics in the 10 ps to 1 ns time scale was obtained using EINS. Values of mean square displacements mainly from protein H atoms were extracted for wild-type P2 and the P38G mutant and compared. Our results show that at physiological temperatures, the P38G mutant is more dynamic than the wild-type P2 protein, especially on a slow 1-ns time scale. Molecular dynamics simulations confirmed the enhanced dynamics of the mutant variant, especially within the portal region in the presence of bound fatty acid. The increased softness of the hinge mutant of human myelin P2 protein is likely related to an enhanced flexibility of the portal region of this fatty acid-binding protein, as well as to its interactions with the lipid bilayer surface requiring conformational adaptations

    The effect of apolipoprotein E polymorphism on serum metabolome - a population-based 10-year follow-up study

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    Apolipoprotein E (apoE) is the key regulator of plasma lipids, mediating altered functionalities in lipoprotein metabolism - affecting the risk of coronary artery (CAD) and Alzheimer's diseases, as well as longevity. Searching pathways influenced by apoE prior to adverse manifestations, we utilized a metabolome dataset of 228 nuclear-magnetic-resonance-measured serum parameters with a 10-year follow-up from the population-based Young Finns Study cohort of 2,234 apoE-genotyped (rs7412, rs429358) adults, aged 24-39 at baseline. At the end of our follow-up, by limiting FDR-corrected p < 0.05, regression analyses revealed 180/ 228 apoE-polymorphism-related associations with the studied metabolites, in all subjects - without indications of apoE x sex interactions. Across all measured apoE-and apoB-containing lipoproteins, e4 allele had consistently atherogenic and epsilon 2 protective effect on particle concentrations of free/esterified cholesterol, triglycerides, phospholipids and total lipids. As novel findings, epsilon 4 associated with glycoprotein acetyls, LDL-diameter and isoleucine - all reported biomarkers of CAD-risk, inflammation, diabetes and total mortality. ApoE-subgroup differences persisted through our 10-year follow-up, although some variation of individual metabolite levels was noticed. In conclusion, apoE polymorphism associate with a complex metabolic change, including aberrations in multiple novel biomarkers related to elevated cardiometabolic and all-cause mortality risk, extending our understanding about the role of apoE in health and disease

    Cardiometabolic Health Among Adult Offspring of Hypertensive Pregnancies: The Cardiovascular Risk in Young Finns Study.

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    BACKGROUND: Cardiometabolic health among adult offspring of hypertensive disorders of pregnancy (HDP) is relatively unknown. We hypothesized that offspring of HDP would have abnormalities in the retinal microvasculature and cardiac structure by midadulthood. METHODS AND RESULTS: The Cardiovascular Risk in Young Finns Study included randomly selected children from 5 Finnish university cities. The mean age of participants was 40 years (range 34-49 years) at the time of retinal photography and cardiac assessment. Offspring born ≥37 weeks of gestation and appropriate for gestational age (n=1006) were included. Offspring of HDP had higher systolic blood pressure (β=4.68, P<0.001), body mass index (β=1.25, P=0.009), and waist circumference (β=0.25, P=0.042), compared with offspring of normotensive pregnancies. However, no differences in fasting glucose, insulin, lipid profile, carotid intima media thickness, or brachial artery flow-mediated dilatation were shown. Retinal arteriolar diameters were narrower (β=-0.43, P=0.009) and longer (β=32.5, P=0.023) and the arteriolar length-to-diameter ratio was higher (β=2.32, P=0.006) among offspring of HDP, after adjustment for age and sex. Left atrial volume indexed to body surface area (β=1.34, P=0.040) was increased. Adjustment for the confounding effects of birth weight, body mass index, smoking and socioeconomic status, and the mediating effect of hypertension had little impact on the associations. CONCLUSIONS: Abnormalities of the retinal microvasculature and cardiac structure are seen in offspring of HDP in midadulthood. These findings may need to be considered in future primary prevention strategies of cardiovascular disease among offspring of HDP

    Does neuregulin-1 play a role in Type A behavior? The cardiovascular risk in young Finns study

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    BACKGROUND: Neuregulin-1 proteins are related to physiological correlates of Type A in terms of cardiac reactivity. Furthermore, neuregulin-1 gene (NRG1) may play a role in cardiovascular disease such as atherosclerosis and coronary heart disease i.e. the suggested "outcomes" of Type A behavior. Therefore, NRG1 is hypothesized to be associated with Type A behavior. METHODS: The study examined whether Type A behavior pattern is associated with the single nucleotide polymorphism (SNP) SNP8NRG221533 of the NRG1. The subjects were 631 men and women participating in the population-based Cardiovascular Risk in Young Finns study in 1992 and 2001. Type A was self-assessed with the Framingham Type A Scale and reassessed nine years later. RESULTS: Type A was associated with NRG1 genotype. Carriers of genotype CC scored lower on Type A compared to the others. CONCLUSION: Our study has pinpointed a SNP in NRG1 that predicts Type A behavior. As previous evidence suggests an association for NRG1 with beta-adrenergic stimulation, its role underlying Type A is discussed

    Comparison Between Nailing and Plating in the Treatment of Distal Tibial Fractures: A Meta-Analysis

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    Background and Aims: To evaluate evidence on the superiority of plate fixation over intramedullary nail fixation in the treatment of distal tibial fractures regarding functional outcomes and complication rates. Material and Methods: Cochrane Controlled Trials Register, Medline, Embase, CINAHL, Scopus, and Web of Science databases were searched in December 2019. The risk of systematic bias was assessed according to the Cochrane Collaboration's domain-based evaluation framework. Results: The search resulted in 514 records, the final sample included 10 randomized controlled trials (782 patients). There were statistically significant differences in operating time (-11.2, 95% confidence interval: -16.3 to -6.1 min), time to partial weight bearing (-0.96, 95% confidence interval: -1.8 to -0.1 weeks), time to full weight bearing (-2.2, 95% confidence interval: -4.32 to -0.01 weeks), the rates of deep infections (risk ratio = 0.37, 95% confidence interval: 0.19 to 0.69), and the rates of soft-tissue complications (risk ratio = 0.52, 95% confidence interval: 0.33 to 0.82) favoring intramedullary nail. Intraoperative blood loss (127.2, 95% confidence interval: 34.7 to 219.7 mL) and postoperative knee pain and stiffness (relative risk = 5.6, 95% confidence interval: 1.4-22.6) showed significant differences favoring plate fixation. When combining all complication rates, the difference was risk ratio = 0.77 (95% confidence interval: 0.63 to 0.95) favoring intramedullary nail. No significant differences in radiation time, length of incision, length of hospital stay, time to return to work, time to union, the rates of healing complications or secondary procedures, ankle pain or stiffness, or functional scores were found. Conclusion: This meta-analysis suggests that intramedullary nail might be slightly superior in reducing postoperative complications and result in slightly faster healing when compared to plate fixation.</div

    Going carless in different urban fabrics : socio-demographics of household car ownership

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    Diverse physical features of urban areas alongside socio-demographic characteristics affect car ownership, and hence the daily mobility choices. As a case of sustainable mobility, we explore how various urban environments and socio-demographics associate with the spatial and social distribution of household car ownership and carlessness in the Helsinki Metropolitan Area, Finland. Three urban fabrics characterizing the study area are established based on the transportation mode (walking, public transportation, or automobile) the physical urban environment primarily supports. The national level Monitoring System of Spatial Structure and Urban Form database, and the National Travel Survey (2016) are utilized to further include spatial and socio-demographic variables into our analysis across these fabrics. Our results show that households with and without cars differ in terms of residential distance to the city center, neighborhood density, house type, and socio-demographic profiles. Single pensioners and students are most likely to be carless, whereas families represent the opposite. Within the carless households the differences are also evident between different groups. For the more affluent households residing in dense and well-connected areas, and mostly possessing driver's licenses, carlessness is presumably a choice. Contrarily, many other carless households represent the less affluent often located in the more distant, low-density, and less accessible areas, while also possessing less driver's licenses, making carlessness more of a constraint, as the local urban fabric does not support such lifestyle. Consequently, carless households should be increasingly recognized as a focus group in sustainable urban planning in terms of identifiable best practices and potential vulnerability.Peer reviewe

    New evidence from plasma ceramides links apoE polymorphism to greater risk of coronary artery disease in Finnish adults

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    apoE, a key regulator of plasma lipids, mediates altered functionalities in lipoprotein metabolism and thus affects the risk of coronary artery disease (CAD). The significance of different apoE polymorphisms remains unclear; although the epsilon 4 allele is clearly associated with increased cholesterol levels (which inform CAD risk), direct studies about apoE polymorphisms on CAD risk and development have yielded controversial results. Furthermore, certain species of ceramides-complex lipids abundant in plasma LDL-are markers of increased risk of myocardial infarction and cardiovascular death. Using a high-throughput MS approach, we quantified 30 molecular plasma ceramide species from a cohort of 2,160 apoE-genotyped (rs7412, rs429358) young adults enrolled in the population-based Cardiovascular Risk in Young Finns Study. We then searched this lipidome data set to identify new indications of pathways influenced by apoE polymorphisms and possibly related to CAD risk. This approach revealed a previously unreported association between apoE polymorphism and a consistently documented high-risk CAD marker, Cer(d18:1/16:0). Compared with the apoE epsilon 3/3 reference group, plasma levels of apoE epsilon 4 were elevated and those of apoE epsilon 2 were lowered in all subjects without evidence of apoE-by-sex interactions. apoE associated with seven ceramides that are connected to atherogenically potent macrophages and/or lipoprotein particles; these associations could indicate a plausible linkage between apoE polymorphism and ceramide metabolism, leading to adverse plasma LDL metabolism and atherogenesis. In conclusion, new evidence from plasma ceramides links apoE polymorphism with an increased risk of CAD and extends our understanding of the role of apoE in health and disease
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