ABSTRACT
The design, development, and successful implementation of pop-up Langmuir probes installed in the water-cooled divertor of W7-X are described. The probes are controlled by drive coils (actuators) installed behind the divertor plates. These drive coils make use of the magnetic field in W7-X to move the probe tips into and out of the plasma. The drive coils were installed in the vacuum vessel after extensively testing the durability of the coils and analyzing the criteria for safe operation. The probe design is carefully tailored for each of the 36 probe tips in order to be suitable for the different magnetic field configurations used in W7-X and ensure that the probes do not present leading edges to the magnetic flux tubes. An electronic bridge circuit is used for measurement to compensate for the effects of signal propagation time on the long cable lengths used. The diagnostic is integrated with the segment control of W7-X for automated operation and control of the diagnostic. The evaluation of the results from the plasma operation is presented after accounting for appropriate sheath expansion for negative bias voltage on the probes.
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PURPOSE: Levonorgestrel-only emergency contraception (EC) inhibits ovulation to prevent fertilization. Misconceptions regarding its mechanism of action contribute to low use in some settings. We aimed to review the mechanism of action of Levonorgestrel EC and assess the evidence for a postovulatory effect on viable pregnancy development in the exposed and subsequent cycles. BASIC PROCEDURES: We searched Pubmed, Embase, Web of Science, clinicaltrials.gov, the Cochrane database, and the US FDA Adverse Event Reporting System. We included studies reporting on the effect of Levonorgestrel EC exposure on (1) ovulation, (2) conception, (3) implantation, (4) ectopic pregnancy, (5) pregnancy viability, and (6) fertility in subsequent cycles. Data were extracted and tabulated from included studies by two researchers. The results were analyzed and summarized in narrative form. MAIN FINDINGS: We included 33 studies. Women exposed to Levonorgestrel EC at or after the LH (luteinizing hormone) surge had similar rates of inhibited ovulation (3 studies) and conception rates (2 studies) as controls. Nine out of ten studies found no difference in endometrial receptivity to implantation after exposure to Levonorgestrel EC compared to controls. The evidence for an association between Levonorgestrel EC and reduced fallopian tube motility or ectopic pregnancy was conflicting. We found no evidence of increased miscarriage or teratogenicity (3 studies) or disrupted menstrual cycle (3 studies) after Levonorgestrel EC exposure compared to controls. PRINCIPAL CONCLUSIONS: This review supports that Levonorgestrel EC taken after ovulation does not affect implantation and results in similar conception rates compared to placebo. There is no evidence that exposure to Levonorgestrel EC affects fetal development, miscarriage, stillbirth, or subsequent menstruations.
Subject(s)
Abortion, Spontaneous , Contraception, Postcoital , Pregnancy, Ectopic , Abortion, Spontaneous/etiology , Contraception, Postcoital/adverse effects , Contraception, Postcoital/methods , Female , Fertility , Humans , Levonorgestrel , Pregnancy , Pregnancy, Ectopic/etiologyABSTRACT
BACKGROUND: The availability of modern contraception including long-acting reversible contraceptives (LARC), is a fundamental component of postabortion care. Findings from a recent randomized controlled trial (RCT) in South Africa comparing immediate to delayed insertion of the copper intrauterine device (IUD) after medical abortion (MA) at 17-20 gestational weeks showed that immediate insertion resulted in higher IUD use at 6 weeks postabortion, but that expulsion rates were significantly higher than for delayed insertion. This study aims to explore barriers, facilitators, and context-specific factors relevant to the implementation of immediate IUD provision after second trimester medical abortion. METHODS: We performed a qualitative study alongside the RCT in which we conducted in-depth interviews with 14 staff providing healthcare to study participants and 24 study participants. Research questions explored barriers and facilitators to implementation of immediate IUD insertion, contraceptive decision-making, and the impact of context and supplementary trial activities on service provision. Interviews were recorded and transcribed, with translation into English if needed. We performed a triangulated thematic analysis at the level of the transcribed interview text. RESULTS: Contraceptive counselling at the abortion facility by a study nurse improved knowledge, corrected misconceptions, and increased demand for the IUD postabortion. Women expressed a clear preference for immediate insertion. Convenience, protection from pregnancy and privacy issues were paramount and women expressed preference for engagement with staff who knew their abortion history, and with whom they had an established connection. Doctors and nurses were generally in favour of immediate insertion and said it could be incorporated into standard care if women wanted this. This contrasted with the need for interventions by the research team to reinforce adherence by staff to provide contraception as allocated during the trial. CONCLUSIONS: Women and staff favour immediate IUD insertion after second trimester medical abortion, but service delivery may require structures that ensure timely insertion postabortion, continuity of care, communication that mitigates loss to follow-up and training of staff to ensure competence.
Subject(s)
Abortion, Induced , Abortion, Spontaneous , Intrauterine Devices , Contraception , Female , Humans , Pregnancy , Pregnancy Trimester, SecondABSTRACT
Equilibrium analysis in fusion devices usually relies on plasma pressure profiles and magnetic measurements outside the plasma. The kinetic profiles can give indirect information about the equilibrium magnetic field, while the stationary magnetic diagnostics cannot resolve current distributions on a smaller scale. This work presents a reciprocating magnetic probe, designed to provide direct plasma response measurements of the magnetic field in the scrape-off layer of Wendelstein 7-X. Hardware design and frequency characteristics are discussed, and a post-processing technique for extending the lower frequency cutoff of the integration scheme is presented.
ABSTRACT
The design and evaluation of the Langmuir probe system used in the first divertor operation phase of Wendelstein 7-X is described. The probes are integrated into the target plates and have individually facetted surfaces to keep the angle of incidence of the magnetic field within an appropriate range for different magnetic configurations. Multiple models for the derivation of plasma parameters from current-voltage characteristics are introduced. These are analyzed with regard to their assumptions and limitations, generalized, and adapted to our use case. A detailed comparison is made to determine the most suitable model. It is found that the choice of model has a large impact, for example, resulting in a change in the inferred temperatures of up to a factor two. This evaluation is implemented in a Bayesian modeling framework and automated to allow for joint analysis with other diagnostics and a replacement of ad hoc assumptions. We rigorously treat parameter uncertainties, revealing strong correlations between them. General and flexible model formulations permit an expansion to additional effects.
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BACKGROUND: Telemedicine is increasingly being used to access abortion services. OBJECTIVE: To assess the success rate, safety, and acceptability for women and providers of medical abortion using telemedicine. SEARCH STRATEGY: We searched PubMed, EMBASE, ClinicalTrials.gov, and Web of Science up until 10 November 2017. STUDY CRITERIA: We selected studies where telemedicine was used for comprehensive medical abortion services, i.e. assessment/counselling, treatment, and follow up, reporting on success rate (continuing pregnancy, complete abortion, and surgical evacuation), safety (rate of blood transfusion and hospitalisation) or acceptability (satisfaction, dissatisfaction, and recommendation of the service). DATA COLLECTION AND ANALYSIS: Quantitative outcomes were summarised as a range of median rates. Qualitative data were summarised in a narrative synthesis. MAIN RESULTS: Rates relevant to success rate, safety, and acceptability outcomes for women ≤10+0 weeks' gestation (GW) ranged from 0 to 1.9% for continuing pregnancy, 93.8 to 96.4% for complete abortion, 0.9 to 19.3% for surgical evacuation, 0 to 0.7% for blood transfusion, 0.07 to 2.8% for hospitalisation, 64 to 100% for satisfaction, 0.2 to 2.3% for dissatisfaction, and 90 to 98% for recommendation of the service. Rates in studies also including women >10+0 GW ranged from 1.3 to 2.3% for continuing pregnancy, 8.5 to 20.9% for surgical evacuation, and 90 to 100% for satisfaction. Qualitative studies on acceptability showed no negative impacts for women or providers. CONCLUSION: Based on a synthesis of mainly self-reported data, medical abortion through telemedicine seems to be highly acceptable to women and providers, success rate and safety outcomes are similar to those reported in literature for in-person abortion care, and surgical evacuation rates are higher. TWEETABLE ABSTRACT: A systematic review of medical abortion through telemedicine shows outcome rates similar to in-person care.
Subject(s)
Abortion, Induced/statistics & numerical data , Patient Acceptance of Health Care/statistics & numerical data , Patient Satisfaction/statistics & numerical data , Telemedicine/statistics & numerical data , Abortion, Induced/methods , Adult , Female , Gestational Age , Humans , Pregnancy , Qualitative Research , Self Report , Telemedicine/methodsABSTRACT
OBJECTIVE: To assess the safety and acceptability of abortion through telemedicine at >9+0 weeks of gestation. DESIGN: Cohort study. SETTING: Poland. POPULATION: Six hundred and fifteen women who requested and underwent a abortion through telemedicine from 1 June to 31 December 2016. METHODS: Risks of adverse outcomes were calculated as adjusted odds ratios (aORs) with 95% confidence intervals (95% CIs) by unconditional logistic regression according to gestational age at abortion: ≤9 or >9 weeks of gestation. MAIN OUTCOME MEASURES: Self-reported clinical visits for complaints related to the abortion within 0-1 days of the treatment, heavy bleeding, pain or bleeding more than expected, and low satisfaction. RESULTS: Among women undergoing a abortion at ≤9 or >9 weeks of gestation, 3.3 versus 11.7% went to hospital with concerns within 0-1 days of the termination (aOR 3.82, 95% CI 1.90-7.69). Among women undergoing a abortion from 11+1 to 14+2 weeks of gestation, the rate was 22.5% (aOR 9.20, 95% CI 3.58-23.60). Among women undergoing a abortion at ≤9 or >9 weeks of gestation, the rate of heavy bleeding was 6.8 versus 10.1% (aOR 1.65, 95% CI 0.90-3.04), the rate of low satisfaction was 2.4 versus 1.6% (aOR 0.69, 95% CI 0.14-3.36), the rate of bleeding more than expected was 45.6 versus 57.8% (aOR 1.26, 95% CI 0.78-2.02), and the rate of pain more than expected was 35.6 versus 38.8% (aOR 1.11, 95% CI 0.71-1.71). CONCLUSIONS: Medical abortion through telemedicine at >9 weeks of gestation is associated with a higher risk of same-day or day-after clinical visits for concerns related to the procedure, and this risk increases with gestational age. Self-reported rates of heavy bleeding, low satisfaction, or unmet expectations with medical abortion do not increase with gestational age. TWEETABLE ABSTRACT: A cohort study shows that abortion through telemedicine at >9 weeks of gestation is associated with more hospital visits but not with increased bleeding.
Subject(s)
Abortifacient Agents/adverse effects , Abortion, Induced/adverse effects , Aftercare/statistics & numerical data , Telemedicine/methods , Uterine Hemorrhage/epidemiology , Abortifacient Agents/administration & dosage , Abortion, Induced/methods , Adolescent , Adult , Female , Gestational Age , Humans , Middle Aged , Odds Ratio , Patient Satisfaction , Poland/epidemiology , Pregnancy , Retrospective Studies , Treatment Outcome , Uterine Hemorrhage/chemically induced , Young AdultABSTRACT
OBJECTIVE: To investigate whether retained placenta in the first generation is associated with an increased risk of retained placenta in the second generation. DESIGN: Population-based cohort study. SETTING: Sweden. POPULATION: Using linked generational data from the Swedish Medical Birth Register 1973-2012, we identified 494 000 second-generation births with information on the birth of the mother (first-generation index birth). For 292 897 of these births there was information also on the birth of the father. METHODS: Risk of retained placenta in the second generation was calculated as adjusted odds ratios (aOR) by unconditional logistic regression with 95% confidence intervals (95% CI) according to whether retained placenta occurred in a first generation birth or not. MAIN OUTCOME: Retained placenta in the second generation. RESULTS: The risk of retained placenta in a second-generation birth was increased if retained placenta had occurred at the mother's own birth (aOR 1.66, 95% CI 1.52-1.82), at the birth of one of her siblings (aOR 1.58, 95% CI 1.43-1.76) or both (aOR 2.75, 95% CI 2.18-3.46). The risk was slightly increased if retained placenta had occurred at the birth of the father (aOR 1.23, 95% CI 1.07-1.41). For preterm births in both generations, the risk of retained placenta in the second generation was increased six-fold if retained placenta had occurred at the mother's birth (OR 6.55, 95% CI 2.68-16.02). CONCLUSION: There is an intergenerational recurrence of retained placenta on the maternal and most likely also on the paternal side. The recurrence risk seems strongest in preterm pregnancies. TWEETABLE ABSTRACT: A population-based cohort study suggests that there is an intergenerational recurrence of retained placenta.
Subject(s)
Genetic Predisposition to Disease/epidemiology , Maternal Inheritance , Paternal Inheritance , Placenta, Retained/genetics , Adult , Cohort Studies , Female , Humans , Infant, Newborn , Logistic Models , Male , Odds Ratio , Pregnancy , Registries , Risk Factors , Sweden/epidemiology , Young AdultABSTRACT
Wendelstein 7-X, a superconducting optimized stellarator built in Greifswald/Germany, started its first plasmas with the last closed flux surface (LCFS) defined by 5 uncooled graphite limiters in December 2015. At the end of the 10 weeks long experimental campaign (OP1.1) more than 20 independent diagnostic systems were in operation, allowing detailed studies of many interesting plasma phenomena. For example, fast neutral gas manometers supported by video cameras (including one fast-frame camera with frame rates of tens of kHz) as well as visible cameras with different interference filters, with field of views covering all ten half-modules of the stellarator, discovered a MARFE-like radiation zone on the inboard side of machine module 4. This structure is presumably triggered by an inadvertent plasma-wall interaction in module 4 resulting in a high impurity influx that terminates some discharges by radiation cooling. The main plasma parameters achieved in OP1.1 exceeded predicted values in discharges of a length reaching 6 s. Although OP1.1 is characterized by short pulses, many of the diagnostics are already designed for quasi-steady state operation of 30 min discharges heated at 10 MW of ECRH. An overview of diagnostic performance for OP1.1 is given, including some highlights from the physics campaigns.
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In the first part of this review, stationary phases (silica, hybrid silica, hydride silica and non-silica stationary phases) were characterized and compared with respect to selectivity, efficiency, resolution, solvent consumption and analysis time. The present review focuses on the thermal and chemical stability of stationary phases. Stationary phases of high chemical and thermal stability are required for separations that are carried over a wide pH and/or temperature range.
Subject(s)
Chromatography, Liquid/methods , Silicates/chemistry , Silicon Dioxide/chemistry , Buffers , Chromatography, Liquid/instrumentation , TemperatureABSTRACT
Free silanols on the surface of silica are the "villains", which are responsible for detrimental interactions of those compounds and the stationary phase (i.e., bad peak shape, low efficiency) as well as low thermal and chemical stability. For these reasons, we began this review describing new silica and hybrid silica stationary phases, which have reduced and/or shielded silanols. At present, in liquid chromatography for the majority of analyses, reversed-phase liquid chromatography is the separation mode of choice. However, the needs for increased selectivity and increased retention of hydrophilic bases have substantially increased the interest in hydrophilic interaction chromatography (HILIC). Therefore, stationary phases and this mode of separation are discussed. Then, non-silica stationary phases (i.e., zirconium oxide, titanium oxide, alumina and porous graphitized carbon), which afford increased thermal and chemical stability and also selectivity different from those obtained with silica and hybrid silica, are discussed. In addition, the use of these materials in HILIC is also reviewed.
Subject(s)
Chromatography, Liquid/instrumentation , Silicates/chemistry , Silicon Dioxide/chemistry , Hydrophobic and Hydrophilic Interactions , Surface PropertiesABSTRACT
An overview of the diagnostics which are essential for the first operational phase of Wendelstein 7-X and the set of diagnostics expected to be ready for operation at this time are presented. The ongoing investigations of how to cope with high levels of stray Electron Cyclotron Resonance Heating (ECRH) radiation in the ultraviolet (UV)/visible/infrared (IR) optical diagnostics are described.
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OBJECTIVE: To evaluate whether defective placentation disorders, i.e. pre-eclampsia, stillbirth, small for gestational age (SGA), and spontaneous preterm birth, are associated with risk of retained placenta. DESIGN: Population-based cohort study. SETTING: Sweden. POPULATION: Primiparous women in Sweden with singleton vaginal deliveries between 1997 and 2009 at 32-41 weeks of gestation (n = 386,607), without placental abruption or infants with congenital malformations. METHODS: Risks were calculated as odds ratios (ORs) by unconditional logistic regression with 95% confidence intervals (95% CIs) after adjustments for maternal, delivery, and infant characteristics. MAIN OUTCOME MEASURE: Retained placenta, defined by the presence of both a diagnostic code (of retained placenta) and a procedure code (for the manual removal of the placenta). RESULTS: The overall rate of retained placenta was 2.17%. The risk of retained placenta was increased for women with pre-eclampsia (adjusted OR, aOR, 1.37, 95% CI 1.21-1.54), stillbirth (aOR 1.71, 95% CI 1.28-2.29), SGA birth (aOR 1.47, 95% CI 1.28-1.70), and spontaneous preterm birth (32-34 weeks of gestation, aOR 2.35, 95% CI 1.97-2.81; 35-36 weeks of gestation, aOR 1.55, 95% CI 1.37-1.75). The risk was further increased for women with preterm pre-eclampsia (aOR 1.69, 95% CI 1.25-2.28) and preterm SGA birth (aOR 2.19, 95% CI 1.42-3.38). There was no association between preterm stillbirth (aOR 1.10, 95% CI 0.63-1.92) and retained placenta, but the exposed group comprised only 15 cases. CONCLUSIONS: Defective placentation disorders are associated with an increased risk of retained placenta. Whether these relationships indicate a common pathophysiology remains to be investigated.
Subject(s)
Infant, Small for Gestational Age , Placenta, Retained/etiology , Pre-Eclampsia , Premature Birth , Stillbirth , Adult , Cohort Studies , Female , Humans , Infant, Newborn , Logistic Models , Odds Ratio , Placenta, Retained/epidemiology , Pregnancy , Registries , Risk Factors , SwedenABSTRACT
Three RP-LC column characterization protocols [Tanaka et al. (1989), Snyder et al. (PQRI, 2002), and NIST SRM 870 (2000)] were evaluated using both Euclidian distance and Principal Components Analysis to evaluate effectiveness at identifying equivalent columns. These databases utilize specific chromatographic properties such as hydrophobicity, hydrogen bonding, shape/steric selectivity, and ion exchange capacity of stationary phases. The chromatographic parameters of each test were shown to be uncorrelated. Despite this, the three protocols were equally successful in identifying similar and/or dissimilar stationary phases. The veracity of the results has been supported by some real life pharmaceutical separations. The use of Principal Component Analysis to identify similar/dissimilar phases appears to have some limitations in terms of loss of information. In contrast, the use of Euclidian distances is a much more convenient and reliable approach. The use of auto scaled data is favoured over the use of weighted factors as the former data transformation is less affected by the addition or removal of columns from the database. The use of these free databases and their corresponding software tools shown to be valid for identifying similar columns with equivalent chromatographic selectivity and retention as a "backup column". In addition, dissimilar columns with complimentary chromatographic selectivity can be identified for method development screening strategies.
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Mobile phase pH and temperature are major factors in determining retention, selectivity and chromatographic performance of ionizable compounds. This imposes a requirement that stationary phases must ideally be stable in both acidic and basic conditions coupled with good thermal stability, in order to be able to chromatograph these compounds in either their ionized or ion-suppressed modes. The development of a range of new high and/or low pH stable silica based RPLC stationary phases (including sub-2 µm fully porous and sub-3 µm fused core-shell materials), which are specially designed for the analysis of ionizable compounds and their chemical and thermal stability is reviewed. The ability to utilize both pH and temperature as selectivity variables allows the chromatographer to exploit a much wider method development design space including previously prohibited alkaline conditions. This greatly increases the probability of satisfying the desired chromatographic selectivity and performance criteria.
Subject(s)
Chromatography, Reverse-Phase/methods , Pharmaceutical Preparations/chemistry , Silicon Dioxide/chemistry , Hydrogen-Ion Concentration , TemperatureABSTRACT
The critical issues in the development of diagnostics, which need to work robust and reliable under quasi-steady state conditions for the discharge durations of 30 min and which cannot be maintained throughout the one week duration of each operation phase of the Wendelstein 7-X stellarator, are being discussed.
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Stationary-phase evaluation in reversed-phase liquid chromatography (RP-LC) is not a straightforward process. A number of tests to characterize and classify stationary phases have been suggested. The results of these various tests, however, do not always describe the real properties of the stationary phase. This study critically compares several tests for RP-LC stationary phases, including the Engelhardt, Tanaka, and SRM 870 tests, as well as an in-house test, with emphasis on the stationary-phase descriptors of hydrophobicity and silanol activity. The stationary phases were prepared by thermal immobilization of poly(methyloctylsiloxane) onto silica. Hydrophobicity data from the tests were generally good and interchangeable between the several tests. In contrast, the silanol activity results of the various tests differ significantly. As a consequence, stationary phase classification with respect to silanol activity depends considerably on the test method applied. A new classification method for silanol activity is proposed.
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A novel stationary phase prepared by the thermal immobilization of poly(dimethylsiloxane) onto the surface of silica (PDMS-SiO(2)) has been described, evaluated and compared with 229 commercially available RP-LC stationary phases using the Tanaka column classification protocol. The phase exhibited many unique chromatographic properties and, based on the phases in the database, was most similar to the fluoroalkylated phases (aside from the obvious lack of fluoro selectivity imposed by the C-F dipole). The phase exhibited classic reversed-phase behaviour in acid mobile phase conditions and mixed-mode reversed-phase/cation-exchange retention behaviour in neutral mobile phase conditions. The phase exhibited acceptable stability at both low and intermediate pH, conditions which should impart optimum chromatographic selectivity to the phase. Retention of basic analytes was shown to occur by a "three site model" as proposed by Neue. This new PDMS-SiO(2) stationary phase is extremely interesting in that the dominancy of its hydrophobic and ion-exchange interactions can be controlled by the influence of mobile phase pH, buffer type and concentration. The PDMS-SiO(2) stationary phase may provide a complementary tool to reversed-phase and HILIC stationary phases. The present results highlight the fact that the type of buffer, its concentration and pH can not only affect peak shape but also retention, selectivity and hence chromatographic resolution. Therefore, in method development and optimization strategies it is suggested that more emphasis should be given to the evaluation of these mobile phase operating parameters especially when basic solutes are involved.
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The effects of mobile phase pH, temperature, buffer type and buffer concentration on the selectivity and stability of four stationary phases, with different PMOS loadings, prepared by the thermal immobilization of poly(methyloctylsiloxane) on to silica (PMOS-SiO2), were evaluated with both hydrophobic and hydrophilic basic solutes. These solutes show longer retention times at near neutral pH, where both the silanols and the basic solutes are partially ionized, and shorter retention times in more alkaline pH, where the silanols are mostly ionized and the basic solutes are not ionized. Increases in temperature and buffer concentration also result in shorter retention times. These PMOS-SiO2 stationary phases are quite stable at low pH and are also stable at ambient temperature (23 °C) using pH 7 phosphate. The PMOS-SiO2 stationary phases are more stable at higher pH using triethylamine (pH 11) and borate (pH 10) buffers than with phosphate and carbonate buffers. Temperature increases stationary phase degradation, while buffer concentration has a minimal effect on stationary phase degradation, indicating that these PMOS-SiO2 stationary phases have stabilities similar to the equivalent chemically bonded phases.
Subject(s)
Chromatography/instrumentation , Chromatography/methods , Laboratory Chemicals/chemistry , Siloxanes/chemistry , Buffers , Hydrogen-Ion Concentration , Silicon Dioxide/chemistry , TemperatureABSTRACT
Complex analyses of polar compounds, especially basic ones, require more selective stationary phases. The present paper describes a stationary phase prepared by thermal immobilization of poly(methyltetradecylsiloxane) onto chromatographic silica (PMTDS-SiO(2)). This stationary phase presents hydrophobic and ion-exchange interactions that confer both high retention and unique selectivities for basic solutes. The influence of ion-exchange interactions is confirmed by the increase in retention factors of basic solutes when the mobile-phase pH changes from acidic to neutral and by the decrease in retention factors when the mobile-phase pH changes from neutral to alkaline. The ion-exchange properties of the stationary phase are enriched in neutral mobile phase (pH 7-7.5) using soft Lewis bases such as tricine and tris as buffers but are suppressed in both acidic (pH 2.5-6) and highly alkaline mobile phases (pH≤10). Increasing both temperature and flow rate permits more rapid separations while maintaining the selectivity. The stability of the stationary phase is evaluated with acid, neutral and alkaline mobile phases.