131 research outputs found

    Exploiting cross-channel quantizer error correlation in time-interleaved analog-to-digital converters

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    Uniform quantizers are often modeled as additive uncorrelated noise sources. This paper explores the validity of the additive noise model in the environment of time-interleaved A/D converters. Cross-channel quantizer error correlation is an important discrepancy that arises for channel time delays in close proximity. It is demonstrated through simulation that negative error correlation occurs for different granularity quantizers in close proximity. Statistical analysis is presented to characterize error correlation between quantizers with different granularity. A technique exploiting this correlation often yields significant performance gains above the optimal additive noise model solution.Fullbright FellowshipIrwin Mark Jacobs and Joan Klein Jacobs Presidential FellowshipTexas Instruments Incorporated. Leadership University Consortium ProgramBAE SystemsAnalog Devices, inc.Lincoln Laborator

    Balance between matrix metalloproteinases (MMP) and tissue inhibitors of metalloproteinases (TIMP) in the cervical mucus plug estimated by determination of free non-complexed TIMP

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    <p>Abstract</p> <p>Background</p> <p>The cervical mucus plug (CMP) is a semi-solid structure with antibacterial properties positioned in the cervical canal during pregnancy. The CMP contains high concentrations of matrix metalloproteinase 8 and 9 (MMP-8, MMP-9) and tissue inhibitor of metalloproteinase 1 (TIMP-1). This indicates a potential to degrade extracellular matrix components depending on the balance between free non-complexed inhibitors and active enzymes.</p> <p>Methods</p> <p>Thirty-two CMPs collected during active labor at term were analyzed. Twelve CMPs were separated into a cellular and an extracellular/fluid phase and analyzed by gelatin and reverse zymography to reveal MMP and TIMP location. Twenty samples were homogenized, extracted and studied by the TIMP activity assay based on gelatin zymography. Enzyme-linked immunosorbent assay (ELISA) was used to determine TIMP-1, MMP-8 and MMP-9 protein concentrations, and gelatin and reverse zymography used to identify gelatinases and TIMPs, respectively. The Western blotting technique was applied for semi-quantification of alpha2-macroglobulin. An ELISA activity assay was used to detect MMP-8 and MMP-9 activity.</p> <p>Results</p> <p>ProMMP-2, proMMP-9, TIMP-1 and TIMP-2 were almost exclusively located in the fluid phase compared to the cellular phase of the CMP. All the extracted samples contained MMP-8, MMP-9, TIMP-1, TIMP-2 and alpha2-macroglobulin. Free non-complexed TIMP was detected in all the samples analyzed by the TIMP activity assay and was associated with TIMP-1 protein (R = 0.71, p < 0.001) and with the TIMP/MMP molar ratio (1.7 (1.1–2.5) (mean (95% confidence interval)) (R = 0.65, p = 0.002). The ELISA activity assay showed no activity from MMP-8 or MMP-9.</p> <p>Conclusion</p> <p>Due to their extracellular location, potential proteolytic activity from neutrophil-derived MMPs in the CMP could exert a biological impact on cervical dilatation and fetal membrane rupture at term. The functional TIMP activity assay, revealing excess non-complexed TIMP, and a molar inhibitor/enzyme ratio above unity, indicate that refined MMP control prevents CMP-originated proteolytic activity in the surrounding tissue.</p

    Downregulation of microRNA-383 is associated with male infertility and promotes testicular embryonal carcinoma cell proliferation by targeting IRF1

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    Our previous studies have shown that microRNA-383 (miR-383) expression is downregulated in the testes of infertile men with maturation arrest (MA). However, the underlying mechanisms of miR-383 involved in the pathogenesis of MA remain unknown. In this study, we showed that downregulation of miR-383 was associated with hyperactive proliferation of germ cells in patients with mixed patterns of MA. Overexpression of miR-383 in NT2 (testicular embryonal carcinoma) cells resulted in suppression of proliferation, G1-phase arrest and induction of apoptosis, whereas silencing of miR-383 reversed these effects. The effects of miR-383 were mediated through targeting a tumor suppressor, interferon regulatory factor-1 (IRF1), and miR-383 was negatively correlated with IRF1 protein expression in vivo. miR-383 inhibited IRF1 by affecting its mRNA stability, which subsequently reduced the levels of the targets of IRF1, namely cyclin D1, CDK2 and p21. Downregulation of IRF1 or cyclin D1, but not that of CDK2, enhanced miR-383-mediated effects, whereas silencing of p21 partially inhibited the effects of miR-383. Moreover, miR-383 downregulated CDK4 by increasing proteasome-dependent degradation of CDK4, which in turn resulted in an inhibition of phosphorylated retinoblastoma protein (pRb) phosphorylation. These results suggest that miR-383 functions as a negative regulator of proliferation by targeting IRF1, in part, through inactivation of the pRb pathway. Abnormal testicular miR-383 expression may potentiate the connections between male infertility and testicular germ cell tumor

    Matrix Metalloproteinase-1 and -9 in Human Placenta during Spontaneous Vaginal Delivery and Caesarean Sectioning in Preterm Pregnancy

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    Preterm birth is a major public health problem in terms of loss of life, long-term and short term disabilities worldwide. The process of parturition (both term and preterm) involves intensive remodelling of the extracellular matrix (ECM) in the placenta and fetal membranes by matrix metalloproteinases (MMPs). Our previous studies show reduced docosahexaenoic acid (DHA) in women delivering preterm. Further omega 3 fatty acids are reported to regulate MMP levels. This study was undertaken to examine the placental levels of MMPs and their association with placental DHA levels in women delivering preterm. The levels of MMP-1 and MMP-9 in 74 women delivering preterm (52 by spontaneous vaginal delivery and 22 by caesarean sectioning) and 75 women delivering at term (59 by spontaneous vaginal delivery and 16 by caesarean sectioning) were determined by enzyme-linked immunosorbent assay (ELISA) and their association with placental DHA was studied. Placental MMP-1 levels were higher (p<0.05) in women delivering preterm (both by spontaneous vaginal delivery and caesarean sectioning) as compared to those delivering at term. In contrast, placental MMP-9 levels in preterm pregnancies was higher (p<0.05) in women with spontaneous vaginal delivery while lower (p<0.05) in women delivering by caesarean sectioning. Low placental DHA was associated with higher placental MMP-9 levels. Our study suggests a differential effect of mode of delivery on the levels of MMPs from placenta. Further this study suggests a negative association of DHA and the levels of MMP-9 in human placenta although the mechanisms need further study

    First-trimester cesarean scar pregnancy: a comparative analysis of treatment options from the international registry

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    Background: A cesarean scar pregnancy is an iatrogenic consequence of a previous cesarean delivery. The gestational sac implants into a niche created by the incision of the previous cesarean delivery, and this carries a substantial risk for major maternal complications. The aim of this study was to report, analyze, and compare the effectiveness and safety of different treatments options for cesarean scar pregnancies managed in the first trimester through a registry. Objective: This study aimed to evaluated the ultrasound findings, disease behavior, and management of first-trimester cesarean scar pregnancies. Study design: We created an international registry of cesarean scar pregnancy cases to study the ultrasound findings, disease behavior, and management of cesarean scar pregnancies. The Cesarean Scar Pregnancy Registry collects anonymized ultrasound and clinical data of individual patients with a cesarean scar pregnancy on a secure, digital information platform. Cases were uploaded by 31 participating centers across 19 countries. In this study, we only included live and failing cesarean scar pregnancies (with or without a positive fetal heart beat) that received active treatment (medical or surgical) before 12+6 weeks' gestation to evaluate the effectiveness and safety of the different management options. Patients managed expectantly were not included in this study and will be reported separately. Treatment was classified as successful if it led to a complete resolution of the pregnancy without the need for any additional medical interventions. Results: Between August 29, 2018, and February 28, 2023, we recorded 460 patients with cesarean scar pregnancies (281 live, 179 failing cesarean scar pregnancy) who fulfilled the inclusion criteria and were registered. A total of 270 of 460 (58.7%) patients were managed surgically, 123 of 460 (26.7%) patients underwent medical management, 46 of 460 (10%) patients underwent balloon management, and 21 of 460 (4.6%) patients received other, less frequently used treatment options. Suction evacuation was very effective with a success rate of 202 of 221 (91.5%; 95% confidence interval, 87.8-95.2), whereas systemic methotrexate was least effective with only 38 of 64 (59.4%; 95% confidence interval, 48.4-70.4) patients not requiring additional treatment. Overall, surgical treatment of cesarean scar pregnancies was successful in 236 of 258 (91.5%, 95% confidence interval, 88.4-94.5) patients and complications were observed in 24 of 258 patients (9.3%; 95% confidence interval, 6.6-11.9). Conclusion: A cesarean scar pregnancy can be managed effectively in the first trimester of pregnancy in more than 90% of cases with either suction evacuation, balloon treatment, or surgical excision. The effectiveness of all treatment options decreases with advancing gestational age, and cesarean scar pregnancies should be treated as early as possible after confirmation of the diagnosis. Local medical treatment with potassium chloride or methotrexate is less efficient and has higher rates of complications than the other treatment options. Systemic methotrexate has a substantial risk of failing and a higher complication rate and should not be recommended as first-line treatment

    Socio-demographic factors associated with pet ownership amongst adolescents from a UK birth cohort

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    Background: In developed nations, pet ownership is common within families. Both physical and psychological health benefits may result from owning a pet during childhood and adolescence. However, it is difficult to determine whether these benefits are due to pet ownership directly or to factors linked to both pet ownership and health. Previous research found associations between a range of socio-demographic factors and pet ownership in seven-year-old children from a UK cohort. The current study extends this research to adolescence, considering that these factors may be important to consider in future Human-Animal Interaction (HAI) research across childhood.Results:The Avon Longitudinal Study of Parents and Children (ALSPAC) collected pet ownership data prospectively via maternal reports from gestation up to age 10 years old and via self-report retrospectively at age 18 for ages 11(n= 3063) to 18 years old (n= 3098) on cats, dogs, rabbits, rodents, birds, fish, tortoise/turtles and horses. The dataset also contains a wide range of potential confounders, including demographic and socio-economic variables.The ownership of all pet types peaked at age 11 (80%) and then decreased during adolescence, with the exclusion of cats which remained constant (around 30%), and dogs which increased through 11–18 years (26–37%). Logistic regression was used to build multivariable models for ownership of each pet type at age 13 years, and the factors identified in these models were compared to previously published data for 7 year-olds in the same cohort. There was some consistency with predictors reported at age 7. Generally sex, birth order, maternal age, maternal education, number of people in the household, house type, and concurrent ownership of other pets were associated with pet ownership at both 7 and 13 years (the direction of association varied according to pet type).Factors that were no longer associated with adolescent pet ownership included child ethnicity, paternal education,and parental social class.Conclusions:A number of socio-demographic factors are associated with pet ownership in childhood and adolescence and they differ according to the type of pet, and age of child. These factors are potential confounders that must be considered in future HAI studies

    Genome-wide methylation analysis identifies genes silenced in non-seminoma cell lines

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    Silencing of genes by DNA methylation is a common phenomenon in many types of cancer. However, the genome wide effect of DNA methylation on gene expression has been analysed in relatively few cancers. Germ cell tumours (GCTs) are a complex group of malignancies. They are unique in developing from a pluripotent progenitor cell. Previous analyses have suggested that non-seminomas exhibit much higher levels of DNA methylation than seminomas. The genomic targets that are methylated, the extent to which this results in gene silencing and the identity of the silenced genes most likely to play a role in the tumours’ biology have not yet been established. In this study, genome-wide methylation and expression analysis of GCT cell lines was combined with gene expression data from primary tumours to address this question. Genome methylation was analysed using the Illumina infinium HumanMethylome450 bead chip system and gene expression was analysed using Affymetrix GeneChip Human Genome U133 Plus 2.0 arrays. Regulation by methylation was confirmed by demethylation using 5-aza-2-deoxycytidine and reverse transcription–quantitative PCR. Large differences in the level of methylation of the CpG islands of individual genes between tumour cell lines correlated well with differential gene expression. Treatment of non-seminoma cells with 5-aza-2-deoxycytidine verified that methylation of all genes tested played a role in their silencing in yolk sac tumour cells and many of these genes were also differentially expressed in primary tumours. Genes silenced by methylation in the various GCT cell lines were identified. Several pluripotency-associated genes were identified as a major functional group of silenced genes

    Clarifying the role of three-dimensional transvaginal sonography in reproductive medicine: an evidenced-based appraisal

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    This overview describes and illustrates the clinical applications of three-dimensional transvaginal sonography in reproductive medicine. Its main applications include assessment of uterine anomalies, intrauterine pathology, tubal patency, polycystic ovaries, ovarian follicular monitoring and endometrial receptivity. It is also useful for detailed evaluation of failed and/or ectopic pregnancy. Three-dimensional color Doppler sonography provides enhanced depiction of uterine, endometrial, and ovarian vascularity
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