355 research outputs found

    Fluid-Dynamic Characterization and Efficiency Analysis in Plastic Separation of the Hydraulic Separator Multidune

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    Recovery of useable plastics from post-consumer and manufacturing waste remains a major recycling challenge. The global consumption of plastics was reported to be 230 million tonnes in 2005 of which 47.5 million tonnes were produced in Europe (25 European Union countries + Norway and Switzerland). Of the European production, only 22 million tonnes were reported as having been collected. Of this collected waste, 4 million tonnes were recycled as a manufacturing feedstock (18%) and 6.4 million tonnes went into energy recovery (29%), with the balance (11.6 million tonnes) probably being disposed in landfills. The recycling of plastics is a process essential to reduce the efflux of materials to landfills and to decrease the production of raw materials. In recent years awareness of the importance of environmental protection has led to the development of different techniques for plastic recycling. One issue related to the recycling of this material is the presence in the market of many types of plastics (polymers with additives), often with similar characteristics that make them difficult to differentiate in the recovery phase. The separator “Multidune” is a hydraulic separator by density. Its name derives from the characteristic undulate profile of the channel where separation occurs. The channel is constructed from a sequence of closed parallel cylindrical tubes welded together in plane which are then sliced down the lateral mid-plane and the lower complex is laterally shifted relative to the upper complex. The Multidune allows solid particle separation according to their specific weight and the velocity field establishing within the apparatus. Previous investigations suggested the flow within the Multidune is organized into three main patterns. Principally, a longitudinal transport flow takes place, where the velocity is high. A particle belonging to this region can move from one camera to another. The second region is the lower recirculation zone with high values of the vorticity field. Particles belonging to this region undergo the vertical impulse of the fluid. The thrust is proportional to the vertical velocity component and, in conjunction with gravity and buoyancy, determines the destiny of a particle. If the thrust is larger than the net weight of the particle, an interaction with the principal transport flow occurs and, consequently, the particle will move to the following chamber. The third region is the upper recirculation zone whose dimensions are smaller than the other recirculation zone. If a particle moves from the principal flow to the secondary vorticity zone, it will have the chance to come back to the previous chamber, assuming the principal transport flow thrust does not prevent it from falling out. Because of the role played by velocity, the fluid dynamic investigation of the Multidune apparatus is a preliminary step to carry out in order to investigate its capability in separating solid particles. For this reason a novel experimental campaign was set up and image analysis was employed to detect the velocity field within the apparatus

    How Much Does AMH Really Vary in Normal Women?

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    Anti-Mullerian Hormone (AMH) is an ovarian hormone expressed in growing follicles that have undergone recruitment from the primordial follicle pool but have not yet been selected for dominance. It is considered an accurate marker of ovarian reserve, able to reflect the size of the ovarian follicular pool of a woman of reproductive age. In comparison to other hormonal biomarkers such as serum FSH, low intra- and intermenstrual cycle variability have been proposed for AMH. This review summarizes the knowledge regarding within-subject variability, with particular attention on AMH intracycle variability. Moreover the impact of ethnicity, body mass index, and smoking behaviour on AMH interindividual variability will be reviewed. Finally changes in AMH serum levels in two conditions of ovarian quiescence, namely contraceptives use and pregnancy, will be discussed. The present review aims at guiding researchers and clinicians in interpreting AMH values and fluctuations in various research and clinical scenarios

    New strategies of ovarian stimulation based on the concept of ovarian follicular waves: From conventional to random and double stimulation

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    The theory of a multicyclic development of follicles during the menstrual cycle prompted new approaches to ovarian stimulation, such as starting gonadotrophins for ovarian stimulation at any time during the menstrual cycle or using double stimulation during it, with stimulation in both the follicular and luteal phases. Because of the asynchrony between endometrial receptivity and embryo development with a ‘non-conventional start’ stimulation, all the oocytes/embryos are generally cryopreserved and transferred subsequently. This deferred transfer policy is currently possible given the advances in vitrification techniques, with success rates comparable to those following transfer with ‘fresh’ embryos. New stimulation approaches, together with advanced cryopreservation techniques, allow for a total ‘disarticulation’ between the time of the menstrual cycle, ovarian stimulation start and embryo transfer. This new approach to ovarian stimulation is particularly useful for women seeking fertility preservation, especially where a shortened time to starting cancer treatment is desirable. Also, poor responders could benefit from the new stimulation protocols by continuing ovarian stimulation after the first oocyte retrieval, thereby obtaining more oocytes or embryos compared with the conventional approach

    How much variation in oocyte yield after controlled ovarian stimulation can be explained? A multilevel modelling study

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    How much variation in oocyte yield after controlled ovarian stimulation (COS) can be accounted for by known patient and treatment characteristics

    Adnexal Torsion during Pregnancy after Oocyte In Vitro Maturation and Intracytoplasmic Sperm Injection Cycle

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    We report a case of right adnexal torsion during pregnancy after an oocyte in vitro maturation and intracitoplasmic sperm injection cycle in patient with polycystic ovary syndrome. A 31-year-old woman with a typical clinical disorder of polycystic ovarian syndrome was included in an oocyte in vitro maturation program. Right adnexal torsion occurred two days after embryo transfer, and laparoscopy detorsion was successfully performed with preservation of adnexa. The patient had a full-term pregnancy and delivered a healthy infant at 40 weeks of gestation. To our knowledge this is the first report of adnexal torsion after an oocyte in vitro maturation and intracitoplasmic sperm injection program

    Antimüllerian hormone in gonadotropin releasing-hormone antagonist cycles: prediction of ovarian response and cumulative treatment outcome in good-prognosis patients

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    ObjectiveTo assess the relationships between serum antimüllerian hormone (AMH) and ovarian response and treatment outcomes in good-prognosis patients undergoing controlled ovarian stimulation using a gonadotropin-releasing hormone (GnRH) antagonist protocol.DesignSecondary analysis of data prospectively collected in a randomized, assessor-blind trial comparing two different gonadotropin preparations with respect to ongoing pregnancy rate.SettingTwenty-five centers in seven countries.Patient(s)749 women, aged 21 to 34 years, with primary diagnosis of infertility being unexplained infertility or mild male factor infertility and with serum follicle-stimulating hormone (FSH) level 1–12 IU/L and antral follicle count (AFC) ≥10.Intervention(s)Controlled ovarian stimulation with highly purified human menopausal gonadotropin (hphMG) or recombinant FSH in a GnRH antagonist cycle with compulsory single-blastocyst transfer and potential subsequent 1-year cryopreserved blastocyst replacement in natural cycles.Main Outcome Measure(s)Relationships between AMH at start of stimulation and ovarian response and treatment outcome.Result(s)Serum AMH concentration was strongly correlated with oocyte yield: AMH accounted for 85%, FSH for 14%, and inhibin B and AFC for <1% each of the explained variation in oocyte yield. Also, AMH showed a high accuracy for the prediction of poor (≤3 oocytes) and high response (≥15 oocytes), which was statistically significantly better than basal FSH, AFC, or inhibin B. AMH was statistically significantly positively associated with ongoing pregnancy rate in the fresh cycle as well as with the 1-year cumulative ongoing pregnancy and live-birth rates.Conclusion(s)There is a positive relationship between AMH and oocyte yield in GnRH antagonist cycles, and AMH is the best predictor for identifying patients with poor and high ovarian response. The positive association between AMH and cumulative live-birth rates after fresh and cryopreserved cycles reflects the availability of more oocytes/blastocysts, not higher quality.Clinical Trial Registration NumberNCT00884221

    How adenomyosis changes throughout pregnancy: A retrospective cohort study

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    Objective To study how adenomyosis changes during pregnancy and to possibly correlate these changes to maternal and fetal outcomes. Methods Retrospective exploratory cohort study including 254 women with a pre-conceptional/first-trimester scan to document adenomyosis and known obstetric outcome. If visible, adenomyosis signs were documented in each trimester and postpartum. Mann-Whitney U tests or chi(2) tests were used for continuous and categorical variables, respectively. Results A globular uterus was reported in 79% (n = 52) of women with adenomyosis in the first trimester, in 38% (n = 20) and 2% (n = 1) of women in the second and third trimesters, respectively, and postpartum in 77% (n = 34) of women. Asymmetrical thickening (n = 20, 30%) and cysts (n = 15, 23%) were only visible in 1st trimester. Adenomyosis was associated with miscarriage (odds ratio [OR] 5.9, 95% confidence interval [CI] 2.4-14.9, P &lt; 0.001) also in normal conception only (OR 5.1, 95% CI 1.8-14.2, P = 0.002) or adjusting for maternal age (adjusted OR 5.9, 95% CI 2.3-15.2, P &lt; 0.001). Gestational age at delivery was lower in adenomyosis (P = 0.004); the cesarean section rate was higher than in controls (OR 2.5, 95% CI 1.3-4.8, P = 0.007) also adjusting for age (adjusted OR 2.07, 95% CI 1.06-4.08, P = 0.035). Conclusions Signs of adenomyosis were visible but progressively disappeared in pregnancy; adenomyosis was associated with an increased risk of early miscarriage. Prospective studies are needed to confirm our results

    Prediction of age at menopause from assessment of ovarian reserve may be improved by using body mass index and smoking status.

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    OBJECTIVE: Menopause is the consequence of exhaustion of the ovarian follicular pool. AMH, an indirect hormonal marker of ovarian reserve, has been recently proposed as a predictor for age at menopause. Since BMI and smoking status are relevant independent factors associated with age at menopause we evaluated whether a model including all three of these variables could improve AMH-based prediction of age at menopause. METHODS: In the present cohort study, participants were 375 eumenorrheic women aged 19-44 years and a sample of 2,635 Italian menopausal women. AMH values were obtained from the eumenorrheic women. RESULTS: Regression analysis of the AMH data showed that a quadratic function of age provided a good description of these data plotted on a logarithmic scale, with a distribution of residual deviates that was not normal but showed significant left-skewness. Under the hypothesis that menopause can be predicted by AMH dropping below a critical threshold, a model predicting menopausal age was constructed from the AMH regression model and applied to the data on menopause. With the AMH threshold dependent on the covariates BMI and smoking status, the effects of these covariates were shown to be highly significant. CONCLUSIONS: In the present study we confirmed the good level of conformity between the distributions of observed and AMH-predicted ages at menopause, and showed that using BMI and smoking status as additional variables improves AMH-based prediction of age at menopause
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