Olivine Crystal Structure-Directed Twinning in Iron Germanium Sulfide (FeGeS) Nanoparticles.

Understanding the microstructure of complex crystal structures is critical for controlling material properties in next-generation devices. Synthetic reports of twinning in bulk and nanostructured crystals with detailed crystallographic characterization are integral for advancing systematic studies of twinning phenomena. Herein, we report a synthetic route to controllably twinned olivine nanoparticles.

Amide-Assisted Synthesis of Iron Germanium Sulfide (FeGeS) Nanostars: The Effect of LiN(SiMe) on Precursor Reactivity for Favoring Nanoparticle Nucleation or Growth.

Olivine FeGeS has been identified as a promising photovoltaic absorber material introduced as an alternate candidate to iron pyrite, FeS. The compounds share similar benefits in terms of elemental abundance and relative nontoxicity, but FeGeS was predicted to have higher stability with respect to decomposition to alternate phases and, therefore, more optimal device performance. Our initial report of the nanoparticle (NP) synthesis for FeGeS was not well understood and required an inefficient 24 h growth to dissolve an iron sulfide impurity.

Total and unopposed estrogen exposure across stages of the transition to menopause.

Detailed characterization of estrogen dynamics during the transition to menopause is an important step toward understanding its potential implications for reproductive cancers developing in the transition years. We conducted a 5-year prospective study of endogenous levels of total and unopposed estrogen. Participants (n=108; ages 25-58 years) collected daily urine specimens for 6 months in each of 5 consecutive years.

Monitoring reproductive aging in a 5-year prospective study: aggregate and individual changes in luteinizing hormone and follicle-stimulating hormone with age.

Objective: This study describes age-related changes in luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in a 5-year prospective study of reproductive aging.

Design: Participants (n = 156 college-educated, white, US women; 25 to 58 y) were recruited from the TREMIN Research Program on Women's Health. They collected daily urine specimens for 6 months in each of 5 consecutive years.

Urinary beta-luteinizing hormone and beta-follicle stimulating hormone immunoenzymometric assays for population research.

Objective: We developed assays for measurement of urinary betaLH and betaFSH under collection and storage conditions typical of non-clinical research settings.

Design And Methods: IEMAs for free betaLH and total betaFSH were validated by standard methods. Stability of urinary betaLH and betaFSH was tested across freeze-thaws and stored long term at 4 degrees C or -20 degrees C, or short term at room temperature, and with heating to dissociate the subunits.

Monitoring reproductive aging in a 5-year prospective study: aggregate and individual changes in steroid hormones and menstrual cycle lengths with age.

Objective: We describe a 5-year prospective study of reproductive aging, and present analyses of steroid hormone and menstrual cycle changes with age.

Design: Participants were college-educated white women, primarily of northern European ancestry, recruited from the Tremin Research Program on Women's Health (n = 156, 25-58 years). In each of 5 consecutive years, they collected daily urine specimens for 6 months and recorded menstrual bleeds for all months.

Stereoselective synthesis of alpha-silylamines by the direct addition of silyl anions to activated imines.

[reaction: see text] A highly efficient stereoselective synthesis of unusual alpha-silylamines via a direct silyl anion addition reaction is reported. This approach is convergent and avoids any problematic aza-Brook shifts of the anionic intermediates. The use of enantiopure tert-butanesulfinyl imines as the electrophiles affords exceedingly high levels of diastereocontrol for the newly formed stereogenic carbon.

Statistical correction for non-parallelism in a urinary enzyme immunoassay.

Our aim was to develop a statistical method to correct for non-parallelism in an estrone-3-glucuronide (E1G) enzyme immunoassay (EIA). Non-parallelism of serially diluted urine specimens with a calibration curve was demonstrated in an EIA for E1G. A linear mixed-effects analysis of 40 urine specimens was used to model the relationship of E1G concentration with urine volume and derive a statistical correction.

Comparison of specific gravity and creatinine for normalizing urinary reproductive hormone concentrations.

Background: Specific gravity (SG) may perform as well as creatinine (CR) correction for adjusting urinary hormone concentrations, as well as offer some advantages. We compared the two methods and applied them to US and Bangladeshi specimens to evaluate their use in different populations.

Methods: Pearson correlations between serum concentrations and SG, CR, and uncorrected urinary concentrations were compared using paired daily urine and serum specimens from one menstrual cycle from 30 US women.