1,823 research outputs found

    DNA methylation associated with postpartum depressive symptoms overlaps findings from a genome-wide association meta-analysis of depression

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    Background Perinatal depressive symptoms have been linked to adverse maternal and infant health outcomes. The etiology associated with perinatal depressive psychopathology is poorly understood, but accumulating evidence suggests that understanding inter-individual differences in DNA methylation (DNAm) patterning may provide insight regarding the genomic regions salient to the risk liability of perinatal depressive psychopathology. Results Genome-wide DNAm was measured in maternal peripheral blood using the Infinium MethylationEPIC microarray. Ninety-two participants (46% African-American) had DNAm samples that passed all quality control metrics, and all participants were within 7 months of delivery. Linear models were constructed to identify differentially methylated sites and regions, and permutation testing was utilized to assess significance. Differentially methylated regions (DMRs) were defined as genomic regions of consistent DNAm change with at least two probes within 1 kb of each other. Maternal age, current smoking status, estimated cell-type proportions, ancestry-relevant principal components, days since delivery, and chip position served as covariates to adjust for technical and biological factors. Current postpartum depressive symptoms were measured using the Edinburgh Postnatal Depression Scale. Ninety-eight DMRs were significant (false discovery rate \u3c 5%) and overlapped 92 genes. Three of the regions overlap loci from the latest Psychiatric Genomics Consortium meta-analysis of depression. Conclusions Many of the genes identified in this analysis corroborate previous allelic, transcriptomic, and DNAm association results related to depressive phenotypes. Future work should integrate data from multi-omic platforms to understand the functional relevance of these DMRs and refine DNAm association results by limiting phenotypic heterogeneity and clarifying if DNAm differences relate to the timing of onset, severity, duration of perinatal mental health outcomes of the current pregnancy or to previous history of depressive psychopathology

    Novel all-optical on-off-keyed to alternate-mark-inversion converter

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    We numerically investigate a novel 40 Gbps OOK to AMI all-optical modulation format converter employing an SOA-based Mach-Zehnder interferometer.  We demonstrate operation with a 27-1 PRBS and explain the phase modulation's relationship with patterning

    All-optical technique for modulation format conversion from on-off-keying to alternate-mark-inversion

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    We propose and numerically investigate for the first time a novel all-optical on-off-keying to alternate-mark-inversion modulation format converter operating at 40 Gbps employing a semiconductor optical amplifier (SOA)-based Mach-Zehnder interferometer (MZI). Wedemonstrate that this SOA-MZI operates as a pulse subtractor, and in the absence of patterning will produce perfectly phase inverted pulses regardless of the individual SOA phase excursions. We use a comprehensive computer model to illustrate the impact of patterning on the output phase modulation which is quantified through the definition of the phase compression factor

    Pattern compensation in SOA-based gates

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    We propose a novel scheme employing complementary data inputs to overcome the patterning normally associated with semiconductor optical amplifier based gates and demonstrate the scheme experimentally at 42.6Gb/s. The scheme not only avoids introducing patterning during switching, but also compensates for much of the patterning present on theinput data. A novel gate was developed for the experiment to provide the complementary signals required for the scheme

    Botulinum Neurotoxins

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    High-bandwidth generation of duobinary and alternate-mark-inversion modulation formats using SOA-based signal processing

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    We report on the novel all-optical generation of duobinary (DB) and alternate-mark-inversion (AMI) modulation formats at 42.6 Gb/s from an input on-off keyed signal. The modulation converter consists of two semiconductor optical amplifier (SOA)-based Mach-Zehnder interferometer gates. A detailed SOA model numerically confirms the operational principles and experimental data shows successful AMI and DB conversion at 42.6 Gb/s. We also predict that the operational bandwidth can be extended beyond 40 Gb/s by utilizing a new pattern-effect suppression scheme, and demonstrate dramatic reductions in patterning up to 160 Gb/s. We show an increasing trade-off between pattern-effect reduction and mean output power with increasing bitrate

    All-optical modulation converter for on-off keying to duobinary and alternate-mark inversion at 42.6 Gbps

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    Advanced modulation formats have become increasingly important as telecoms engineers strive for improved tolerance to both linear and nonlinear fibre-based transmission impairments. Two important modulation schemes are Duobinary (DB) and Alternate-mark inversion (AMI) [1] where transmission enhancement results from auxiliary phase modulation. As advanced modulation formats displace Return-to-zero On-Off Keying (RZ-OOK), inter-modulation converters will become increasingly important. If the modulation conversion can be performed at high bitrates with a small number of operations per bit, then all-optical techniques may offer lower energy consumption compared to optical-electronic-optical approaches. In this paper we experimentally demonstrate an all-optical system incorporating a pair of hybrid-integrated semiconductor optical amplifier (SOA)-based Mach-Zehnder interferometer (MZI) gates which translate RZ-OOK to RZ-DB or RZ-AMI at 42.6 Gbps. This scheme includes a wavelength conversion to arbitrary output wavelength and has potential for high-level photonic integration, scalability to higher bitrates, and should exhibit regenerative properties [2]

    Development of a multivariable risk model integrating urinary cell DNA methylation and cell-free RNA data for the detection of significant prostate cancer

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    Background: Prostate cancer exhibits severe clinical heterogeneity and there is a critical need for clinically implementable tools able to precisely and noninvasively identify patients that can either be safely removed from treatment pathways or those requiring further follow up. Our objectives were to develop a multivariable risk prediction model through the integration of clinical, urine-derived cell-free messenger RNA (cf-RNA) and urine cell DNA methylation data capable of noninvasively detecting significant prostate cancer in biopsy naïve patients. Methods: Post-digital rectal examination urine samples previously analyzed separately for both cellular methylation and cf-RNA expression within the Movember GAP1 urine biomarker cohort were selected for a fully integrated analysis (n = 207). A robust feature selection framework, based on bootstrap resampling and permutation, was utilized to find the optimal combination of clinical and urinary markers in a random forest model, deemed ExoMeth. Out-of-bag predictions from ExoMeth were used for diagnostic evaluation in men with a clinical suspicion of prostate cancer (PSA ≥ 4 ng/mL, adverse digital rectal examination, age, or lower urinary tract symptoms). Results: As ExoMeth risk score (range, 0-1) increased, the likelihood of high-grade disease being detected on biopsy was significantly greater (odds ratio = 2.04 per 0.1 ExoMeth increase, 95% confidence interval [CI]: 1.78-2.35). On an initial TRUS biopsy, ExoMeth accurately predicted the presence of Gleason score ≥3 + 4, area under the receiver-operator characteristic curve (AUC) = 0.89 (95% CI: 0.84-0.93) and was additionally capable of detecting any cancer on biopsy, AUC = 0.91 (95% CI: 0.87-0.95). Application of ExoMeth provided a net benefit over current standards of care and has the potential to reduce unnecessary biopsies by 66% when a risk threshold of 0.25 is accepted. Conclusion: Integration of urinary biomarkers across multiple assay methods has greater diagnostic ability than either method in isolation, providing superior predictive ability of biopsy outcomes. ExoMeth represents a more holistic view of urinary biomarkers and has the potential to result in substantial changes to how patients suspected of harboring prostate cancer are diagnosed

    The evolution of parental cooperation in birds

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    Parental care is one of the most variable social behaviors and it is an excellent model system to understand cooperation between unrelated individuals. Three major hypotheses have been proposed to explain the extent of parental cooperation: sexual selection, social environment, and environmental harshness. Using the most comprehensive dataset on parental care that includes 659 bird species from 113 families covering both uniparental and biparental taxa, we show that the degree of parental cooperation is associated with both sexual selection and social environment. Consistent with recent theoretical models parental cooperation decreases with the intensity of sexual selection and with skewed adult sex ratios. These effects are additive and robust to the influence of life-history variables. However, parental cooperation is unrelated to environmental factors (measured at the scale of whole species ranges) as indicated by a lack of consistent relationship with ambient temperature, rainfall or their fluctuations within and between years. These results highlight the significance of social effects for parental cooperation and suggest that several parental strategies may coexist in a given set of ambient environment
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