Temporally versatile polarization entanglement from Bragg reflection waveguides.

Bragg reflection waveguides emitting broadband parametric downconversion (PDC) have been proven to be well suited for the on-chip generation of polarization entanglement in a straightforward fashion [Sci. Rep.3, 2314 (2013)SRWSDA2045-232210.1038/srep02314]. Here, we investigate how the properties of the created states can be modified by controlling the relative temporal delay between the pair of photons created via PDC. Our results offer an easily accessible approach for changing the coherence of the polarization entanglement, in other words, to tune the phase of the off-diagonal elements of the density matrix. Furthermore, we provide valuable insight into the engineering of these states directly at the source.

Three out of four disease-modifying anti-rheumatic drug-naïve rheumatoid arthritis patients meet 28-joint Disease Activity Score remission at 12 months: results from the FIN-ERA cohort.

OBJECTIVE: To assess what proportion of patients with disease-modifying anti-rheumatic drug (DMARD)-naïve early rheumatoid arthritis (ERA) reach 28-joint Disease Activity Score (DAS28) remission over 1 year, and remission variability across clinics in Finland. METHOD: Patients with DMARD-naïve newly diagnosed inflammatory arthritis were recruited. The proportion of patients in 28-joint Disease Activity Score with three variables (DAS28-3) remission was compared across sites. Repeated measures were analysed using a mixed models approach with appropriate distribution and link function. RESULTS: In total, 611 patients were recruited at five sites: 67% were female; the mean (sd) age was 57 (16) years; 71% and 68% were positive for rheumatoid factor and anti-cyclic citrullinated peptides, respectively; and 23% had radiographic erosions. A total of 506 (83%) fulfilled the American College of Rheumatology/European League Against Rheumatism 2010 classification criteria for rheumatoid arthritis for further analyses. DAS28-3 remission was met by 68% and 75% at 3 and 12 months, respectively. The clinical site had no effect on remission when adjusted for confounders. At baseline, 68% used methotrexate-based combination therapy, and 31% used triple therapy with methotrexate, hydroxychloroquine, and sulphasalazine (the Fin-RACo regimen). In multivariate analysis, the only independent predictors of DAS28-3 remission at 12 months were lower baseline DAS28-3 and triple therapy as the initial treatment. CONCLUSION: Three out of four DMARD-naïve ERA patients in Finland are in remission during the first year from the diagnosis. High remission rates were achieved for most patients with the use of conventional synthetic DMARDs in combination. Treatment of DMARD-naïve ERA patients with the FIN-RACo regimen is a predictor of DAS28-3 remission in real-life rheumatology settings.

Uncovering dispersion properties in semiconductor waveguides to study photon-pair generation.

We investigate the dispersion properties of ridge Bragg-reflection waveguides to deduce their phasematching characteristics. These are crucial for exploiting them as sources of parametric down-conversion (PDC). In order to estimate the phasematching bandwidth we first determine the group refractive indices of the interacting modes via Fabry-Perot experiments in two distant wavelength regions. Second, by measuring the spectra of the emitted PDC photons, we gain access to their group index dispersion. Our results offer a simple approach for determining the PDC process parameters in the spectral domain, and provide important feedback for designing such sources, especially in the broadband case.

Mode-resolved Fabry-Perot experiment in low-loss Bragg-reflection waveguides.

Based on the interaction between different spatial modes, semiconductor Bragg-reflection waveguides (BRWs) provide a highly functional platform for non-linear optics. For achieving any desired quantum optical functionality, we must control and engineer the properties of each spatial mode. To reach this purpose we extend the Fabry-Perot technique and achieve a detailed linear optical characterization of dispersive multimode semiconductor waveguides. With this efficient broadband spectral method we gain direct experimental access to the relevant modes of our BRWs and determine their group velocities. Furthermore, we show that our waveguides have lower than expected loss coefficients. This renders them suitable for integrated quantum optics applications.

Testing spectral filters as Gaussian quantum optical channels.

We experimentally investigate the mode characteristics of multimode radiation fields propagating through frequency-dependent Gaussian channels. After manipulating the twin beams emitted from a conventional parametric downconversion source via spectral filtering, we study the changes in their mode characteristics, utilizing the joint normalized correlation functions. While filtering reduces the number of spectral modes, it also leads to an apparent mode mismatch, which destroys the perfect photon-number correlation between the twin beams, and influences the mode properties of heralded states.

Accessing higher order correlations in quantum optical states by time multiplexing.

We experimentally measured higher order normalized correlation functions (NCF) of pulsed light with a time-multiplexing detector. We demonstrate excellent performance of our device by verifying unity valued NCF up to the eighth order for coherent light and factorial dependence of the NCF for pseudothermal light. We applied our measurement technique to a type-II parametric down-conversion source to investigate mutual two-mode correlation properties and ascertain nonclassicality.

Producing high fidelity single photons with optimal brightness via waveguided parametric down-conversion.

Parametric down-conversion (PDC) offers the possibility to control the fabrication of non-Gaussian states such as Fock states. However, in conventional PDC sources energy and momentum conservation introduce strict frequency and photon number correlations, which impact the fidelity of the prepared state. In our work we optimize the preparation of single-photon Fock states from the emission of waveguided PDC via spectral filtering. We study the effect of correlations via photon number resolving detection and quantum interference. Our measurements show how the reduction of mixedness due to filtering can be evaluated. Interfering the prepared photon with a coherent state we establish an experimentally measured fidelity of the produced target state of 78%.

Photon number statistics of multimode parametric down-conversion.

We experimentally analyze the complete photon number statistics of parametric down-conversion and ascertain the influence of multimode effects. Our results clearly reveal a difference between single-mode theoretical description and the measured distributions. Further investigations assure the applicability of loss-tolerant photon number reconstruction and prove strict photon number correlation between signal and idler modes.

Prospective meta-analysis of interleukin 1 gene complex polymorphisms confirms associations with ankylosing spondylitis.

OBJECTIVES: The aim of the current study was to determine the contribution of interleukin (IL)1 gene cluster polymorphisms previously implicated in susceptibility for ankylosing spondylitis (AS) to AS susceptibility in different populations worldwide. METHODS: Nine polymorphisms in the IL1 gene cluster members IL1A (rs2856836, rs17561 and rs1894399), IL1B (rs16944), IL1F10 (rs3811058) and IL1RN (rs419598, the IL1RA VNTR, rs315952 and rs315951) were genotyped in 2675 AS cases and 2592 healthy controls recruited in 12 different centres in 10 countries. Association of variants with AS was tested by Mantel-Haenszel random effects analysis. RESULTS: Strong association was observed with three single nucleotide polymorphisms (SNPs) in the IL1A gene (rs2856836, rs17561, rs1894399, p = 0.0036, 0.000019 and 0.0003, respectively). There was no evidence of significant heterogeneity of effects between centres, and no evidence of non-combinability of findings. The population attributable risk fraction of these variants in Caucasians is estimated at 4-6%. CONCLUSIONS: This study confirms that IL1A is associated with susceptibility to AS. Association of the other IL1 gene complex members could not be excluded in specific populations. Prospective meta-analysis is a useful tool in confirmation studies of genes associated with complex genetic disorders such as AS, providing sufficiently large sample sizes to produce robust findings often not achieved in smaller individual cohorts.

Variant mannose-binding lectin 2 genotype is a risk factor for reactive systemic amyloidosis in rheumatoid arthritis.

OBJECTIVE: The aim of this study was to investigate whether polymorphism of the mannose-binding lectin 2 (MBL2) gene is related to the occurrence of systemic AA amyloidosis in patients with rheumatoid arthritis (RA). METHODS: MBL2 structural gene polymorphisms at codon 52 (CGT-->TGT, Arg-->Cys; D), codon 54 (GGC-->GAC, Gly-->Asp; B) and codon 57 (GGA-->GAA, Gly--> Glu; C), and MBL2 promoter region polymorphism at position -221 (G-->C) were examined in 57 patients with RA complicated by biopsy-proven reactive amyloidosis and 51 control RA patients without amyloid. RESULTS: A strong association was found between the presence of a structural MBL2 gene variant O (B, D or C) and the occurrence of amyloidosis in RA patients: 29 of 57 (50.9%) of the RA patients with amyloid had a variant allele compared with 12 of 51 (23.5%) of the RA patients without amyloid (OR 3.37, 95% CI 1.47-7.72; P = 0.004). CONCLUSION: We conclude that variant MBL2 structural genotype constitutes a significant risk factor for reactive amyloidosis in RA and that the increased risk is probably related to MBL-mediated impairment of mononuclear phagocyte function.

Finnish HLA studies confirm the increased risk conferred by HLA-B27 homozygosity in ankylosing spondylitis.

OBJECTIVE: To determine the influence of HLA-B27 homozygosity and HLA-DRB1 alleles in the susceptibility to, and severity of, ankylosing spondylitis in a Finnish population. METHODS: 673 individuals from 261 families with ankylosing spondylitis were genotyped for HLA-DRB1 alleles and HLA-B27 heterozygosity/homozygosity. The frequencies of HLA-B27 homozygotes in probands from these families were compared with the expected number of HLA-B27 homozygotes in controls under Hardy-Weinberg equilibrium (HWE). The effect of HLA-DRB1 alleles was assessed using a logistic regression procedure conditioned on HLA-B27 and case-control analysis. RESULTS: HLA-B27 was detected in 93% of cases of ankylosing spondylitis. An overrepresentation of HLA-B27 homozygotes was noted in ankylosing spondylitis (11%) compared with the expected number of HLA-B27 homozygotes under HWE (4%) (odds ratio (OR) = 3.3 (95% confidence interval, 1.6 to 6.8), p = 0.002). HLA-B27 homozygosity was marginally associated with reduced BASDAI (HLA-B27 homozygotes, 4.5 (1.6); HLA-B27 heterozygotes, 5.4 (1.8) (mean (SD)), p = 0.05). Acute anterior uveitis (AAU) was present in significantly more HLA-B27 positive cases (50%) than HLA-B27 negative cases (16%) (OR = 5.4 (1.7 to 17), p<0.004). HLA-B27 positive cases had a lower average age of symptom onset (26.7 (8.0) years) compared with HLA-B27 negative cases (35.7 (11.2) years) (p<0.0001). CONCLUSIONS: HLA-B27 homozygosity is associated with a moderately increased risk of ankylosing spondylitis compared with HLA-B27 heterozygosity. HLA-B27 positive cases had an earlier age of onset of ankylosing spondylitis than HLA-B27 negative cases and were more likely to develop AAU. HLA-DRB1 alleles may influence the age of symptom onset of ankylosing spondylitis.

Finnish case-control and family studies support PTPN22 R620W polymorphism as a risk factor in rheumatoid arthritis, but suggest only minimal or no effect in juvenile idiopathic arthritis.

Several studies have identified the PTPN22 allelic variant 1858 C/T that encodes the R620W amino-acid change as a putative susceptibility factor in autoimmune diseases. The current study was undertaken to examine a large cohort of Finnish rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA) subjects using both population control and, importantly, family-based association methods. The latter is particularly important when, as is the case for the 1858 C/T polymorphism, the frequency of the variant allele (T) differs in both major ancestral populations and in subpopulations. The analysis of rheumatoid factor-positive 1030 RA probands from Finland provides strong support for association of this variant in both population studies (allele specific odds ratio (OR)=1.47, 95% confidence interval (CI)=1.27-1.70, P=3 x 10(-7)) and in family studies (P<10(-6)). In contrast, no allelic association was seen with JIA (230 probands) and only weak evidence for a genotypic effect of 1858T homozygotes was observed in this population.

Capability for daily activities in old people with rheumatoid arthritis: a population based study.

OBJECTIVE: To describe the functional capacity for daily activities in old people with clinical rheumatoid arthritis (including juvenile rheumatoid arthritis (JRA)) in a population based cohort. METHODS: A cohort of 700 people was randomly collected from the population older than 75 years in a Finnish town. Altogether 601 persons (86%) participated. Data were collected from clinical records and by interview, clinical examination, and questionnaire. Ability to carry out activities of daily living (ADL) was assessed by the Barthel index, and the IADL (instrumental activities of daily living) by the Lawton and Brody questionnaire. RESULTS: 16 people had clinical rheumatoid arthritis (one with JRA). The prevalence was 16/601 (2.7% (95% confidence interval, 1.7% to 4.5%)). Eight patients with rheumatoid arthritis (50%) obtained the best possible ADL figures, while three (19%) had very poor results. Seven (44%) could not dress themselves without help. Three (19%) were unable to walk, and five (31%) could not climb stairs. Sex and age adjusted results showed no statistical difference (ADL and IADL) between patients with clinical rheumatoid arthritis and rest of the cohort. Four patients (25%) had dementia, which was associated with the poor functional capacity. CONCLUSIONS: The prevalence of the disease was unexceptional. The ability of old people with rheumatoid arthritis to carry out activities of daily living did not differ from the general population, but the disease may lead to severe disability on an individual level, especially when associated with dementia. It therefore remains a considerable challenge to the health care and social systems.

Anaemia of chronic disease in AA amyloidosis is associated with allele 2 of the interleukin-1beta-511 promoter gene and raised levels of interleukin-1beta and interleukin-18.

OBJECTIVE: In amyloid A (AA) amyloidosis the receptor for advanced glycation end products is a target for the circulating amyloid precursor protein (SAA) resulting in upregulation of the proinflammatory cytokine pathway. Besides inducing hepatic SAA synthesis the interleukin-1 cytokine family is involved in the regulation of haematopoiesis. We therefore studied the relationship between the circulating levels of interleukin-1beta (IL-1beta) and interleukin-18 (IL-18), a new member of the IL-1 complex, as well as polymorphisms within the IL-1 cluster with the occurrence of anaemia in patients with AA amyloidosis. DESIGN, SETTING AND SUBJECTS: The study included 54 adult patients with biopsy-proven reactive amyloidosis allocated into three groups on the basis of haemoglobin (Hb) level: group I included all patients with Hb < 110 g L(-1) (n = 16); group II patients (Hb > 110 g L(-1), n = 16) were selected to match group I patients with respect to sex, age, underlying disease (seropositive, erosive rheumatoid arthritis) and renal function; and group III patients (n = 38) represented all patients (unselected) with Hb > or = 110 g L(-1). Gene polymorphisms were studied by polymerase chain reaction restriction length assay and included the base exchange at position-889 of the IL-1alpha gene, the polymorphic region at position-511 and the polymorphic locus at exon 5, position +3954 of the IL-1beta gene, as well as the IL-1 receptor antagonist (IL-1Ra) exon 2 polymorphism caused by the 86-bp tandem repeats. Plasma IL-1beta, IL-1alpha, IL-18, IL-1 Ra, SAA, ferritin, soluble transferrin receptor and erythropoietin levels were studied by enzyme immunoassays. RESULTS: Circulating IL-beta and IL-18 were significantly raised in the anaemic patients with AA amyloidosis when compared with group II patients (matched, Hb > 110 g L(-1)) as well as group III patients (nonmatched, Hb > or = 110 g L(-1)). A significant inverse relationship was found between IL-1beta and haemoglobin levels, as well as between IL-18 and haemoglobin levels. The frequency of allele 2 (T) of the IL-1beta-511 promoter gene was significantly increased and that of allele 1 (C) decreased in anaemic amyloid patients (group I) when compared with group II and III patients. Circulating IL-1beta levels tended to be higher amongst the IL-1beta-511 allele 2 carriers than amongst the noncarriers, as well as amongst the anaemic amyloid patients filling all criteria of anaemia of chronic disease. CONCLUSION: The occurrence of anaemia in patients with AA amyloidosis is associated with allele 2 (T) of the IL-1beta-511 promoter gene and elevated levels of circulating IL-1beta and IL-18. In AA amyloidosis the raised cytokine levels may generate a vicious cycle leading to accelerated amyloidogenesis, suppression of erythropoiesis and aggravation of the underlying inflammatory disorder.

A novel human leucocyte antigen-DRB1 genotyping method based on multiplex primer extension reactions.

We have developed and validated a semi-automated fluorescent method of genotyping human leucocyte antigen (HLA)-DRB1 alleles, HLA-DRB1*01-16, by multiplex primer extension reactions. This method is based on the extension of a primer that anneals immediately adjacent to the single-nucleotide polymorphism with fluorescent dideoxynucleotide triphosphates (minisequencing), followed by analysis on an ABI Prism 3700 capillary electrophoresis instrument. The validity of the method was confirmed by genotyping 261 individuals using both this method and polymerase chain reaction with sequence-specific primer (PCR-SSP) or sequencing and by demonstrating Mendelian inheritance of HLA-DRB1 alleles in families. Our method provides a rapid means of performing high-throughput HLA-DRB1 genotyping using only two PCR reactions followed by four multiplex primer extension reactions and PCR-SSP for some allele groups. In this article, we describe the method and discuss its advantages and limitations.

The effect of transforming growth factor beta1 gene polymorphisms in ankylosing spondylitis.

OBJECTIVES: To determine whether genetic polymorphisms in or near the transforming growth factor beta1 (TGFB1) locus were associated with susceptibility to or severity of ankylosing spondylitis (AS). METHODS: Five intragenic single-nucleotide polymorphisms (SNP) and three microsatellite markers flanking the TGFB1 locus were genotyped. Seven hundred and sixty-two individuals from 184 multiplex families were genotyped for the microsatellite markers and two of the promoter SNPs. One thousand and two individuals from 212 English and 170 Finnish families with AS were genotyped for all five intragenic SNPs. A structured questionnaire was used to assess the age of symptom onset, disease duration and disease severity scores, including the BASDAI (Bath Ankylosing Spondylitis Disease Activity Index) and BASFI (Bath Ankylosing Spondylitis Functional Index). RESULTS: A weak association was noted between the rare TGFB1 +1632 T allele and AS in the Finnish population (P = 0.04) and in the combined data set (P = 0.03). No association was noted between any other SNPs or SNP haplotype and AS, even among those families with positive non-parametric linkage scores. The TGFB1 +1632 polymorphism was also associated with a younger age of symptom onset (English population, allele 2 associated with age of onset greater by 4.2 yr, P = 0.05; combined data set, allele 2 associated with age of onset greater by 3.2 yr, P = 0.02). A haplotype of coding region SNPs (TGFB1 +869/+915+1632 alleles 2/1/2) was associated with age of symptom onset in both the English parent-case trios and the combined data set (English data set, haplotype 2/1/2 associated with age of onset greater by 4.9 yr, P = 0.03; combined data set, haplotype 2/1/2 associated with greater age of onset by 4.2 yr, P = 0.006). Weak linkage with AS susceptibility was noted and the peak LOD score was 1.3 at distance 2 cM centromeric to the TGFB1 gene. No other linkage or association was found between quantitative traits and the markers. CONCLUSION: This study suggests that the polymorphisms within the TGFB1 gene play at most a small role in AS and that other genes encoded on chromosome 19 are involved in susceptibility to the disease.

Albumin as a marker of plasma transudation in experimental skin lesions.

Liquid chromatography measurements of albumin levels were obtained for experimental incision wounds, excoriations, and heat and freezing injuries of different ages. Hemoglobin levels in tissue specimens were measured and an equivalent amount of blood-related albumin was subtracted from the analysis results. In specimens taken immediately after death, the mean albumin level as compared to control skin was increased by about 2-fold in freezing injuries aged 60 min. In all other lesions, the same increase was observed even after 30 min. The mean albumin level was about 3-fold as compared with the control skin in excoriations aged 30 min, heat and freezing injuries aged 4 h, and incision wounds aged 12 h. An approximately 5-fold increase was seen in heat and freezing injuries aged 1 and 2 weeks. A marked decrease occurred in mean albumin levels in all lesions aged 4 weeks. An increase in albumin in wounds and excoriations was demonstrable also in specimens taken 3 days postmortem. Postmortem hypostasis resulted in a 1.1 to 1.4-fold increase in mean albumin levels in wounds and excoriations inflicted 1 min postmortem.

Tumor necrosis factor alpha, its soluble receptor I, and -308 gene promoter polymorphism in patients with rheumatoid arthritis with or without amyloidosis: implications for the pathogenesis of nephropathy and anemia of chronic disease in reactive amyloidosis.

OBJECTIVE: To study tumor necrosis factor alpha (TNFalpha) -308 gene promoter polymorphism and circulating levels of TNFalpha and soluble TNF receptor type I (sTNFRI) in rheumatoid arthritis (RA) patients with and without reactive amyloidosis. METHODS: In a retrospective study, we examined 55 RA patients with biopsy-proven reactive amyloidosis and 55 control RA patients without amyloidosis (matched for age, sex, rheumatoid factor titer, and RA duration). Inflammatory activity was assessed by measuring the erythrocyte sedimentation rate and C-reactive protein level. TNFalpha gene promoter polymorphism was studied using polymerase chain reaction-restriction fragment length polymorphism assay. Cytokine and receptor levels were measured by enzyme-linked immunoassays. RESULTS: Patients with RA and amyloidosis had significantly higher TNFalpha and sTNFRI levels than did the control RA patients. The increased circulating levels of TNFalpha correlated with interleukin-18 levels, but not with the serum amyloid A protein levels or with TNFalpha -308 gene promoter polymorphism (reported to be associated with high TNFalpha levels and certain disease susceptibilities). In the patients with RA and amyloidosis, those with anemia had significantly higher TNFalpha and sTNFRI levels than did those without anemia, and circulating TNFalpha and sTNFRI levels correlated negatively with hemoglobin concentrations. In the patients with RA and amyloidosis, those with nephropathy had significantly higher TNFalpha and sTNFRI levels than did those without nephropathy; in patients with isolated proteinuria (but no creatinine elevation) the TNFalpha level was also significantly increased, indicating that the TNFalpha elevation was not merely a consequence of impaired renal function. CONCLUSION: This study shows that circulating levels of TNFalpha and sTNFRI are significantly increased in RA patients with amyloidosis as compared with control RA patients without amyloidosis and that the increased levels may be implicated in the pathogenesis of certain disease manifestations, including anemia of chronic disease and renal pathology in reactive amyloidosis.