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1.
Steroids ; 207: 109427, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38663566

ABSTRACT

A variety of progestogens are widely used by women for contraception and menopausal hormone therapy. The progestogens undergo extensive metabolism by oral and parenteral routes of administration to form many metabolites. Although a small number of metabolites have been shown to be biologically active, most have not been tested for biologic activity. The present review shows that we know most about progesterone metabolism, followed by the metabolism of levonorgestrel and norethindrone. Very few studies have been carried out on metabolism of most of the progestogens. The clinical significance of this deficiency is that those progestogen metabolites that bind to the progesterone receptors may also bind to other steroid receptors and be responsible for some of the well-documented side effects of administered progestogens. We also discuss how obesity and genetic polymorphisms alter progestogen metabolism, and how development of oral progestogen formulations that are targeted to the colon, where the concentration of steroid-metabolizing enzymes is much lower than in the proximal gut, may have a beneficial effect on progestogen metabolism.


Subject(s)
Progestins , Humans , Progestins/metabolism , Female , Menopause/metabolism , Menopause/drug effects , Contraception , Hormone Replacement Therapy , Animals
2.
J Assist Reprod Genet ; 40(6): 1281-1290, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37058259

ABSTRACT

PURPOSE: To (1) prospectively characterize the incidence of decision regret among women considering planned oocyte cryopreservation (planned OC), comparing those who pursued treatment vs those who did not freeze eggs, and (2) to identify baseline predictors for future decision regret. METHODS: A total of 173 women seen in consultation for planned OC were followed prospectively. Surveys were administered at (1) baseline (< 1 week after initial consultation) and (2) follow-up, 6 months after planned OC among participants who froze eggs or 6 months following consultation in the absence of further communication to pursue treatment. The primary outcome was the incidence of moderate-to-severe decision regret, indicated by a Decision Regret Scale score > 25. We also examined predictors of regret. RESULTS: The incidence of moderate-to-severe regret over the decision to freeze eggs was 9% compared to 51% over the decision not to pursue treatment. Among women who froze eggs, adequacy of information at baseline to decide about treatment (aOR 0.16, 95% CI 0.03, 0.87) and emphasis on future parenthood (aOR 0.80, 95% CI 0.66, 0.99) were associated with reduced odds of regret. Forty-six percent of women who froze eggs regretted not doing so earlier. Among women who did not freeze eggs, the primary reasons were financial and time constraints, correlating with increased odds of decision regret in an exploratory analysis. CONCLUSIONS: Among women undergoing planned OC, the incidence of decision regret is low compared to the regret confronting women seen in consultation for planned OC but who do not pursue treatment. Provider counseling is key to offset the regret risk.


Subject(s)
Fertility Preservation , Female , Animals , Fertility Preservation/psychology , Prospective Studies , Cryopreservation , Emotions , Oocytes
3.
J Assist Reprod Genet ; 40(5): 1099-1107, 2023 May.
Article in English | MEDLINE | ID: mdl-36943573

ABSTRACT

PURPOSE: To examine patient and hospital characteristics related to seasonal fluctuation in in vitro fertilization (IVF). METHODS: This retrospective cohort study examined 33,077 oocyte retrievals identified in the National Ambulatory Surgery Sample. Exposure assignment was monthly IVF encounters: low-volume months (<25%ile), mid-volume months (≥25/<75%ile), and high-volume months (>75%ile). Main outcomes were patient and hospital characteristics related to the exposure groups, assessed with a multinomial regression model. RESULTS: The median IVF encounters were 977 per month, ranging from 657 to 1074 (absolute-difference 417). January, July, and December were the lowest-quartile volume months, ranging from 657 to 710 encounters per month (low-volume months). May, August, and November were the top-quartile volume months, ranging from 1049 to 1074 encounters per month (high-volume months). In a multivariable analysis, patients undergoing IVF in the low-volume months were younger and less likely to have infertility or comorbidities. Patients undergoing IVF in the high-volume months were more likely to have lower household income and receive IVF at urban teaching facilities. Northeastern residents were less likely to have IVF in the low-volume months but more likely to have IVF in the high-volume months. Sensitivity analyses showed that the lowest-to-highest variability in monthly IVF encounters was higher in Northeast region compared to other regions (320 vs 50-128); infertility patients compared to those without (317 vs 190); privately insured patients compared to self-pay (227 vs 156); and older patients compared to younger (234 vs 192). CONCLUSION: This study suggests substantial seasonal fluctuation in IVF oocyte retrieval in the USA based on patient and hospital factors.


Subject(s)
Fertilization in Vitro , Infertility , United States/epidemiology , Pregnancy , Female , Humans , Retrospective Studies , Seasons , Ovulation Induction , Pregnancy Rate
4.
F S Rep ; 3(4): 361-365, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36568937

ABSTRACT

Objective: To examine patient characteristics among those who selected the long-acting reversible contraception (LARC) and surgical sterilization methods at vaginal delivery. Design: Retrospective cohort study. Setting: The National Inpatient Sample. Patients: A total of 8,013,785 vaginal deliveries from October 2016 to December 2019. Interventions: Exposure assignment per LARC (subdermal contraceptive implant [implants] or intrauterine device [IUD]) or surgical sterilization (bilateral salpingectomy [BS] or bilateral tubal ligation [BTL]) type. Main Outcome Measures: Utilization trends of LARC or surgical sterilization, assessed with linear segmented regression with log-transformation, and differences in patient characteristics per the exposure strata (implants vs. IUD in the LARC group and BS or BTL in the surgical sterilization group), assessed using the multivariate binary logistic regression model. Results: In a comparison between LARC and surgical sterilization, surgical sterilization use decreased from 1.90% to 1.55% (18.4% relative decrease), whereas LARC use increased from 0.35% to 1.02% (191% relative increase). In the LARC group, implant use (from 0.12% to 0.50%) increased more compared with IUD use (from 0.22% to 0.52%): relative increase, 317% vs. 136%. In the surgical sterilization group, BTL use decreased from 0.66% to 0.18% (72.7% relative decrease), whereas BS use was statistically unchanged (from 1.24% to 1.37%). In a multivariate analysis, recent year remained an independent characteristic for implant use in the LARC group and BS use in the surgical sterilization group. Moreover, in both LARC and surgical sterilization strata, procedure choices significantly differed on the basis of patient, pregnancy, hospital, and delivery factors. Conclusions: Immediate postpartum contraception choice has evolved in recent years in the United States with an increasing demand for the LARC methods with implants at the time of vaginal delivery.

5.
Eur J Obstet Gynecol Reprod Biol ; 279: 77-83, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36272244

ABSTRACT

OBJECTIVE: Cesarean delivery on maternal request (elective-CD) increased between 1999 and 2015 in the United States, but multiple studies have reported the association between elective-CD and adverse maternal and neonatal outcomes. More contemporary trends and outcomes are currently unknown. The objective of the current study was to examine contemporaneous trends and outcomes of patients who had elective-CD in the United States. METHODS: This is a retrospective cohort study querying the Healthcare Cost and Utilization Project's National Inpatient Sample from January 2016 to December 2019. A three-step exclusion approach was used to identify the surrogate for elective-CD (prior uterine scar, maternal / fetal indications for CD, and labor). The primary outcome was temporal trend of elective-CD. The secondary outcomes included severe maternal morbidity in low-risk vaginal delivery candidates, assessed with inverse probability of treatment weighting propensity score. RESULTS: Among 14,648,135 all deliveries for national estimates, 184,945 (1.26 %) patients had elective-CD. The number of patients undergoing elective-CD decreased from 1.35 % to 1.13 % among all deliveries (16.3 % relative-decrease; P-trend < 0.001) and from 4.14 % to 3.51 % among all CD cases (15.2 % relative-decrease, P-trend = 0.002) between QT1/2016 and QT4/2019. The decreasing trend of elective-CD remained independent in multivariable analysis: odds ratio (OR) compared to 2016, 0.96 (95 % confidence interval [CI] 0.95-0.97) for 2017, 0.94 (95 %CI 0.93-0.95) for 2018, and 0.87 (95 %CI 0.86-0.89) for 2019. In a propensity score weighted model among low-risk vaginal delivery candidates, patients in the elective-CD group were more likely to have severe maternal morbidity compared to those in the non-elective-CD group (OR 2.01, 95 %CI 1.87-2.15). CONCLUSIONS: This national-level analysis suggests that the number of elective-CD is gradually decreasing in recent years in the United States.


Subject(s)
Cesarean Section , Labor, Obstetric , Pregnancy , Infant, Newborn , Female , Humans , United States/epidemiology , Retrospective Studies , Cesarean Section/adverse effects , Delivery, Obstetric , Elective Surgical Procedures/adverse effects
6.
AJOG Glob Rep ; 2(4): 100111, 2022 Nov.
Article in English | MEDLINE | ID: mdl-36311297

ABSTRACT

BACKGROUND: Severe maternal morbidity refers to the most serious complications of pregnancy. Whether severe maternal morbidity is associated with post-traumatic stress disorder is currently under active investigation. OBJECTIVE: This study aimed to examine the association between severe maternal morbidity and post-traumatic stress disorder at delivery. STUDY DESIGN: This was a retrospective cohort study querying the Healthcare Cost and Utilization Project's National Inpatient Sample, which included 12,857,721 patients for national estimates who had vaginal or cesarean deliveries between January 2016 and December 2019. Patients with mental health conditions other than post-traumatic stress disorder and substance use disorder were excluded. Severe maternal morbidity was defined according to the Centers for Disease Control and Prevention definition (a total of 21 indicators). Main outcomes were trends and characteristics related to post-traumatic stress disorder, assessed with a multivariable binary logistic regression model. Sensitivity analysis included subcohort assessment restricted to patients per clinical and obstetrical demographics. RESULTS: A total of 8880 patients had a diagnosis of post-traumatic stress disorder during the hospital admission for delivery (prevalence rate, 6.9 per 10,000). The prevalence rate of post-traumatic stress disorder increased from 5.0 to 8.8 per 10,000 deliveries between 2016 and 2019. This increasing trend remained independent in multivariable analysis. The adjusted odds ratio, compared with 2016, was 1.26 (95% confidence interval, 1.19-1.35) for 2017, 1.50 (95% confidence interval, 1.41-1.60) for 2018, and 1.73 (95% confidence interval, 1.63-1.84) for 2019. Severe maternal morbidity occurred in 210,605 (1.6%) patients. Patients who had severe maternal morbidity were more likely to have a diagnosis of post-traumatic stress disorder than those without severe maternal morbidity (12.8 vs 6.8 per 10,000 deliveries; adjusted odds ratio, 1.57; 95% confidence interval, 1.39-1.78) in multivariable analysis. This association remained robust in several subcohort analyses including (1) participants aged ≤35 years (adjusted odds ratio, 1.62; 95% confidence interval, 1.41-1.86), (2) those aged ≤35 years without medical comorbidity (adjusted odds ratio, 2.01; 95% confidence interval, 1.70-2.37), and (3) those aged <35 years without medical comorbidity, cesarean delivery, and preterm delivery (adjusted odds ratio, 4.52; 95% confidence interval, 3.56-5.74). CONCLUSION: There has been a gradual increase in the number of patients with a diagnosis of post-traumatic stress disorder at delivery in recent years among those without other mental health or substance use conditions. These data suggest that there is a possible association between severe maternal morbidity and post-traumatic stress disorder.

7.
Hum Reprod Open ; 2021(3): hoab023, 2021.
Article in English | MEDLINE | ID: mdl-34337160

ABSTRACT

STUDY QUESTION: Are follicular fluid (FF), arsenic (As), mercury (Hg), cadmium (Cd) and lead (Pb) concentrations associated with IVF outcomes among women undergoing IVF? SUMMARY ANSWER: There was a non-linear association between higher FF Hg concentration and a lower likelihood of biochemical pregnancy and live birth. Higher FF Pb concentration was also associated with a lower probability of live birth. WHAT IS KNOWN ALREADY: Previous research suggests that toxic elements may affect fertility among couples conceiving with and without assistance. However, the results have been inconsistent, possibly related in part to exposure misclassification. Very few studies have used ovarian FF to measure toxic elements, as it requires an invasive collection procedure, yet it may offer a more accurate estimate of a biologically effective dose than blood or urine. STUDY DESIGN SIZE DURATION: This is a prospective study of 56 women undergoing IVF, from October 2015 to June 2017. FF was collected for analysis on the day of oocyte retrieval. PARTICIPANTS/MATERIALS SETTING METHODS: As, Cd, Hg and Pb were determined in 197 FF specimens, using inductively coupled plasma tandem mass spectrometry. FF glutathione peroxidase, glutathione reductase, total glutathione-S-transferase, superoxide dismutase, arylesterase and paraoxonase (PON1p) activities were measured using kinetic enzyme assays. MAIN RESULTS AND THE ROLE OF CHANCE: Non-linear associations were detected, in which the probabilities of biochemical pregnancy (P = 0.05) and live birth (P = 0.05) were lower in association with FF Hg greater than ∼0.51 µg/l Hg, adjusted for age, race, cigarette smoking and recent seafood consumption. Higher FF Pb was also associated with a lower likelihood of live birth (relative risk (RR) = 0.68, 95% CI: 0.46, 1.00; P = 0.05). We also found a suggestive, although imprecise, antagonizing mediating effect of PON1p activity on the association between FF Pb and live birth (-28.3%; 95% CI: -358%, 270%). LIMITATIONS REASONS FOR CAUTION: The results should be interpreted judiciously given the limited sample size and difficulty accounting for correlated data in generalized additive models and mediation analyses. Additionally, women undergoing IVF are highly selected with respect to age and socioeconomic status, and so the generalizability of the results may be limited. WIDER IMPLICATIONS OF THE FINDINGS: Overall, the results suggest that FF Hg was associated with a lower likelihood of biochemical pregnancy and live birth, with a potential threshold effect, and that higher FF Pb was associated with a lower probability of live birth. These results may help to guide clinical recommendations for limiting the exposure of patients to Hg and Pb and ultimately improve IVF success rates. STUDY FUNDING/COMPETING INTERESTS: This work was funded in part by the National Institute of Environmental Health Sciences (NIEHS), grant number 1R56ES023886-01, to the University at Albany (M.S.B.), and in part by the National Institute of Environmental Health Sciences (NIEHS), grant number 1U2CES026542-01, to the Wadsworth Center (P.J.P.). The authors declare no competing interests. TRIAL REGISTRATION NUMBER: N/A.

8.
Int J Hyg Environ Health ; 234: 113751, 2021 05.
Article in English | MEDLINE | ID: mdl-33882414

ABSTRACT

Ensuring harmonization of (ultra-)trace element measurements in non-traditional matrices is a particular analytical challenge that is highlighted in this work for seminal plasma as part of the developmental core at the Wadsworth Center Human Health Exposure Analysis Resource Targeted Laboratory. Seminal plasma was collected from 39 male partners of women undergoing in vitro fertilization and analyzed by inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) following deproteinization with concentrated HNO3. Validation was accomplished using: 1) two aqueous NIST SRMs; 2) a seminal plasma QC pool, characterized via standard additions; 3) standard additions on a subset of samples; and 4) sample duplicates. Agreement with NIST certified or reference values were obtained to within ±15% for the SRMs, and agreement between aqueous calibration values and standard additions values agreed to within ±10-20% for all elements. Standard additions of seminal plasma samples revealed varying matrix effects for Cu and Cr that were not found for the pooled samples. Duplicate analyses agreed to within ±10-30% depending on element. A potential source of contamination in colloidal silica used for processing seminal plasma was identified that requires further study. Comparisons with literature indicate lack of consensus for As, Cd, Cr, Mn, Pb, and V content in seminal plasma. Further work is needed to improve harmonization of future studies.


Subject(s)
Trace Elements , Biological Monitoring , Calibration , Female , Humans , Male , Semen , Tandem Mass Spectrometry
9.
Ecotoxicol Environ Saf ; 209: 111733, 2021 Feb.
Article in English | MEDLINE | ID: mdl-33385679

ABSTRACT

Both essential and non-essential elements have been associated with female reproductive function in epidemiologic investigations, including among IVF populations. To date, most investigators have used blood or urine to assess biomarkers of exposure, with few employing ovarian follicular fluid (FF). FF may offer a more direct "snapshot" of the oocyte microenvironment than blood or urine, however previous studies report follicle-to-follicle variability in FF constituents that may contribute to exposure misclassification. Our objectives were to investigate sources of trace element variability, to estimate FF biomarker reliability among women undergoing IVF (n = 34), and to determine the minimum number of follicles required to estimate subject-specific mean concentrations. We measured As, Hg, Cd, Pb, Cu, Mn, Se, and Zn in FF samples using inductively coupled plasma tandem mass spectrometry. Inter-subject (between-women) variability contributed most of the variability in FF element concentrations, with ovarian, follicular, and analytical as smaller sources of variability. The proportion of variability attributable to sources between-follicles differed by age, body mass index (BMI), race, and cigarette smoking for Cu, Se, and Zn, by BMI and cigarette smoking for As, by primary infertility diagnosis for Hg, Cu, Se, and Zn, and by ovarian stimulation protocol for Mn and Se. Four to five individual follicles were sufficient to estimate subject-specific mean Cu, Se, and Zn concentrations, while >14 were necessary for As, Hg, Cd, Pb, and Mn. Overall, our results suggest that FF is a suitable source of biomarkers of As and Hg exposure in ovarian follicles. Although limited in size, our study offers the most comprehensive exploration of biological variation in FF trace elements to date and may provide guidance for future studies of ovarian trace element exposures.


Subject(s)
Follicular Fluid/metabolism , Reproducibility of Results , Trace Elements/metabolism , Adult , Female , Fertilization in Vitro , Follicular Fluid/chemistry , Humans , Mercury/analysis , Oocytes , Ovarian Follicle , Trace Elements/analysis
10.
Reprod Toxicol ; 99: 56-64, 2021 01.
Article in English | MEDLINE | ID: mdl-33271283

ABSTRACT

Phthalates are reproductive toxicants in experimental animal studies and exposure has been associated with infertility in human populations, although the results have been inconsistent. To help to address the data gap, we conducted a hypothesis-generating investigation of associations between urinary phthalate metabolites and reproductive outcomes among women (n = 56) and their male partners (n = 43) undergoing in vitro fertilization (IVF). Urine was collected from participants on the day of oocyte retrieval. Samples were analyzed for a series of phthalates, MEP, MBP, MPP, MHxP, MEHP, MEHHP, MECPP, MiNP, MiDP, MCHP, and MBzP, using liquid chromatography-tandem mass spectrometry. We employed Poisson regression with robust variance estimation to estimate associations between urinary phthalate levels and biochemical pregnancy and live birth, adjusted for partner's concentration and confounding factors. Doublings in women's MBP (relative risk (RR) = 0.32, 95 % CI: 0.13, 0.78), and men's MEHP (RR = 0.28, 95 % CI: 0.09, 0.83), were associated with a lower likelihood for pregnancy. Doublings in women's (RR = 0.08, 95 % CI: 0.01, 0.67) and men's (RR = 0.13, 95 % CI: 0.02, 0.92) MHxP were associated with a lower likelihood of live birth. Our results suggest that phthalate exposure may impact IVF outcomes, and underscore the importance of including male partners when investigating the impact of phthalate exposure on IVF. These results also suggest that clinical recommendations should include male partners for limiting phthalate exposure. Still, a larger and more comprehensive investigation is necessary to more definitively assess the risks.


Subject(s)
Environmental Exposure , Environmental Pollutants/urine , Fertilization in Vitro , Phthalic Acids/urine , Adult , Biological Monitoring , Female , Humans , Male , Pregnancy , Pregnancy Outcome
11.
Int J Hyg Environ Health ; 229: 113567, 2020 08.
Article in English | MEDLINE | ID: mdl-32599562

ABSTRACT

Phthalates have been implicated as reproductive toxicants in animal models and in human populations. This study examined associations between potential exposure sources and urinary phthalate metabolite concentrations among women (n = 56) and their male partners (n = 43) undergoing in vitro fertilization (IVF). On the day of oocyte retrieval, participants provided urine samples and completed questionnaires detailing use of personal care products (PCPs), and consumption of medications, foods, and beverages in the preceding 24 h. Urine was analyzed for MEP, MBP, MPP, MHxP, MEHP, MEHHP, MECPP, MiNP, MiDP, MCHP, and MBzP, via liquid chromatography-tandem mass spectrometry. We employed principal component analysis (PCA) to summarize exposure sources and regression models to estimate associations between exposure patterns and urinary phthalate metabolites, adjusted for confounding variables. Among women, application of more body washes and eye creams, and consumption of more supplements, was associated with greater urinary MECPP [relative difference = 1.36 (95% CI: 1.28, 1.45)] and the molar sum of DEHP metabolites, including MEHP, MEHHP, and MECPP [∑DEHP; 1.26 (95% CI: 1.17, 1.34)]. Among men, consumption of more supplements and allergy medications was associated with greater urinary MECPP, MEHHP, and ∑DEHP [relative difference = 1.13 (95% CI: 1.02, 1.23)] concentrations. Identifying differences in sources of phthalate exposure may help clinicians to intervene to reduce exposure as part of a comprehensive strategy to help improve IVF outcomes.


Subject(s)
Environmental Pollutants/urine , Infertility/urine , Phthalic Acids/urine , Adult , Anti-Allergic Agents , Cosmetics , Dietary Supplements , Environmental Exposure , Female , Fertilization in Vitro , Food Contamination , Food Packaging , Humans , Infertility/therapy , Male
12.
Environ Res ; 188: 109753, 2020 09.
Article in English | MEDLINE | ID: mdl-32554271

ABSTRACT

Human exposure to non-essential toxic metals such as cadmium (Cd), mercury (Hg), and lead (Pb), and metalloids such as arsenic (As) commonly occurs through diet. Toxic trace element exposures have been reported in association with fertility and fecundity in epidemiologic studies even at low to moderate levels. While most previous studies employed blood and urine biomarkers of exposure, few have assessed toxic trace elements in ovarian follicular fluid (FF), which surrounds the developing oocyte and hence may better reflect concentrations potentially affecting reproductive outcomes. Our objective was to identify dietary predictors of FF toxic trace elements in n = 56 women (mean age: 38.3 years) undergoing in vitro fertilization (IVF) at the University of California at San Francisco. We determined As, Hg, Cd, and Pb in 197 FF specimens, collected on the day of oocyte retrieval, using inductively coupled plasma tandem mass spectrometry. A comprehensive food frequency questionnaire was used to assess the weekly and annual dietary "patterns" of participants. Consumption of specific seafood items and turkey were correlated with individual FF toxic trace elements. We also found that each unit higher seafood consumption in the past week dominated by mollusks, shrimp, and bass was associated with 60% higher FF As (95% confidence interval (CI): 25%, 105%) and FF Hg (95%CI: 7%, 136%) concentrations. Higher annual seafood consumption dominated by urchin, crab, and trout was associated with 16% higher FF As (95%CI: -2%, 38%) and 31% higher FF Hg (95%CI: 7%, 60%) concentrations per unit intake. No associations were noted between diet and Cd and Pb levels in FF. Overall, our results suggest that higher seafood consumption contributes to elevated levels of As and Hg in FF. These findings are consistent with previous IVF studies that assessed toxic trace element exposures in blood and urine. To our knowledge, this is the first study to report that diet might be a source of As, Hg, Cd, and Pb in FF.


Subject(s)
Arsenic , Mercury , Adult , Animals , Cadmium , Female , Fertilization in Vitro , Follicular Fluid , Humans , Seafood/analysis
13.
J Anal At Spectrom ; 34(4): 741-752, 2019 Apr 01.
Article in English | MEDLINE | ID: mdl-31036984

ABSTRACT

Follicular fluid (FF), which is the fluid that envelops the developing oocyte (egg cell) in the ovary, can be analyzed to assess trace element content as well as to determine potential exposure to toxic elements in women seeking in vitro fertilization (IVF) treatment. Such measurements may be useful in establishing associations with potential adverse effects on oocyte viability and subsequent pregnancy outcomes. The principal goal of this study was to leverage the next generation of inorganic mass spectrometry based on ICP-MS/MS to address the numerous analytical challenges of (ultra-)trace element analysis of human FF specimens. Ultra-trace element measurements are defined by the Clinical Laboratory Standards Institute as fluid concentrations below 10 µg L-1 or tissue mass fractions below 1 µg g-1. Stringent pre-analytical procedures were developed to minimize exogenous contamination during FF specimen collection and storage in a prospective study of 56 women seeking IVF treatment. ICP-MS/MS instrumental parameters were carefully optimized, and the method validated for 11 biologically important elements that included 4 at trace levels (Cu, Se, Sr, and Zn) and 7 at ultra-trace levels (As, Cd, Co, Mo, Mn, Hg, and Pb). Method limits of detection (LODs) for ultra-trace elements varied from 5.6 ng L-1 for Cd to 0.11 µg L-1 for Mo. A total of 197 human FF specimens were analyzed using the proposed ICP-MS/MS method with 84% of specimens detectable for Pb and 100% detectable for Co, Cu, Mn, Mo, Sr, and Zn. The method based on ICP-MS/MS was compared to a previous method developed for FF using SF-ICP-MS.

14.
J Am Chem Soc ; 136(42): 15093-101, 2014 Oct 22.
Article in English | MEDLINE | ID: mdl-25254646

ABSTRACT

A novel electron acceptor was synthesized from one-step functionalization of the readily available indigo dye. The resulting bay-annulated indigo (BAI) was utilized for the preparation of a series of novel donor-acceptor small molecules and polymers. As revealed experimentally and by theoretical calculations, substituted BAIs have stronger electron accepting characteristics when compared to several premier electron deficient building blocks. As a result, the donor-acceptor materials incorporating BAI acceptor possess low-lying LUMO energy levels and small HOMO-LUMO gaps. In situ grazing incidence wide-angle X-ray scattering studies of the thin films of BAI donor-acceptor polymers indicated improved crystallinity upon thermal treatment. Field effect transistors based on these polymers show excellent ambipolar transporting behavior, with the hole and electron mobilities reaching 1.5 and 0.41 cm(2) V(-1) s(-1), respectively, affirming BAI as a potent electron accepting unit for high performance organic electronic materials.

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