Tunability in Heterobimetallic Complexes Featuring an Acyclic "Tiara" Polyether Motif.

Both cyclic "crown" and acyclic "tiara" polyethers have been recognized as useful for the binding of metal cations and enabling the assembly of multimetallic complexes. However, the properties of heterobimetallic complexes built upon acyclic polyethers have received less attention than they deserve. Here, the synthesis and characterization of a family of eight redox-active heterobimetallic complexes that pair a nickel center with secondary redox-inactive cations (K, Na, Li, Sr, Ca, Zn, La, and Lu) bound in acyclic polyether "tiara" moieties are reported.

Activation and Functionalization of the Uranyl Ion by Electrochemical Reduction.

Interconversion of the oxidation states of uranium enables separations and reactivity schemes involving this element and contributes to technologies for recycling of spent nuclear fuels. The redox behaviors of uranium species impact these processes, but use of electrochemical methods to drive reactions of molecular uranium complexes and to obtain molecular insights into the outcomes of electrode-driven reactions has received far less attention than it deserves. Here, we show that electro-reduction of the uranyl ion (UO) can be used to promote stepwise functionalization of the typically unreactive oxo groups with exogenous triphenylborane (BPh) serving as a moderate electrophile, avoiding the conventional requirement for a chemical reductant.

Detecting defects: low initial serum human chorionic gonadotropin (hCG) level may predict future fetal anomalies following frozen embryo transfer (FET).

Purpose: To investigate the relationship between early serum hCG levels after frozen embryo transfer and fetal anomalies.

Methods: This was a case-control study at a single academic fertility center between 1/2010 and 12/2021, including all patients who underwent euploid frozen embryo transfers resulting in any fetal anomaly confirmed at the time of induced abortion > 10 weeks or any anomaly reported at delivery. Controls included patients with healthy live births matched for age and day/grade of embryo after euploid FET.

Beyond the egg: sperm source does not impact cumulative live birth rates in autologous oocyte cryopreservation patients when adjusted for oocyte age.

Purpose: To assess the impact of sperm source on cumulative live birth rate (CLBR) after oocyte thaw in autologous oocyte cryopreservation (AOC) patients.

Methods: A retrospective cohort study of autologous oocyte thaw patients at an urban academic fertility center from 2006 to 2021. Patients were stratified by sperm source [partner sperm (PS) vs.

Healthy live births achieved from embryos diagnosed as non-mosaic segmental aneuploid.

Purpose: To investigate pregnancy outcomes resulting from transfer of embryos with non-mosaic (NM) segmental aneuploid (SA) results following preimplantation genetic testing for aneuploidy (PGT-A).

Methods: All patients who underwent frozen embryo transfer (FET) of at least one embryo with a NM-SA between March 2021 and April 2024 were retrospectively reviewed. Primary outcomes included live birth rate (LBR) and results of prenatal diagnosis.

Redox properties of [Cp*Rh] complexes supported by mono-substituted 2,2'-bipyridyl ligands.

The redox properties of half-sandwich rhodium complexes supported by 2,2'-bipyridyl (bpy) ligands can be readily tuned by selection of an appropriately substituted derivative of bpy, but the influences of single substituents on the properties of such complexes are not well documented, as disubstituted bpy variants are much more common. Here, the synthesis, characterization, and redox properties of two new [Cp*Rh] complexes (where Cp* is η-1,2,3,4,5-pentamethylcyclopentadienyl) supported by the uncommon mono-substituted ligands 4-chloro-2,2'-bipyridyl (mcbpy) and 4-nitro-2,2'-bipyridyl (mnbpy) are reported. Single-crystal X-ray diffraction studies and related spectroscopic experiments confirm installation of the single substituents (-Cl and -NO, respectively) on the bipyridyl ligands; the precursor monosubstituted ligands were prepared a divergent route from unsubstituted bpy.

Preparation of Neptunyl and Plutonyl Acetates To Access Nonaqueous Transuranium Coordination Chemistry.

Uranyl diacetate dihydrate is a useful reagent for the preparation of uranyl (UO) coordination complexes, as it is a well-defined stoichiometric compound featuring moderately basic acetates that can facilitate protonolysis reactivity, unlike other anions commonly used in synthetic actinide chemistry such as halides or nitrate. Despite these attractive features, analogous neptunium (Np) and plutonium (Pu) compounds are unknown to date. Here, a modular synthetic route is reported for accessing stoichiometric neptunyl(VI) and plutonyl(VI) diacetate compounds that can serve as starting materials for transuranic coordination chemistry.

Maternal age at transfer following autologous oocyte cryopreservation is not associated with live birth rates.

Purpose: Our aim was to evaluate if maternal age at transfer following autologous oocyte cryopreservation is associated with live birth rate (LBR).

Methods: We performed a retrospective cohort study of all patients who thawed autologous oocytes and then underwent a single frozen euploid embryo transfer between 2011 and 2021 at a large urban university-affiliated fertility center. Each oocyte thaw patient was matched 2:1 to in vitro fertilization (IVF) patients who underwent single embryo transfer < 1 year after retrieval.

Entropy Drives Accelerated Ion Diffusion upon Carbon Dioxide Expansion of Electrolytes.

Carbon dioxide-expanded liquids, organic solvents with high concentrations of soluble carbon dioxide (CO) at mild pressures, have gained attention as green catalytic media due to their improved properties over traditional solvents. More recently, carbon dioxide-expanded electrolytes (CXEs) have demonstrated improved reaction rates in the electrochemical reduction of CO, by increasing the rate of delivery of CO to the electrode while maintaining facile charge transport. However, recent studies indicate that the limiting behavior of CXEs at higher CO pressures is a decline in solution conductivity due to reduced polarity, leading to poorer charge screening and greater ion pairing.

Trivalent Cations Slow Electron Transfer to Macrocyclic Heterobimetallic Complexes.

Incorporation of secondary redox-inactive cations into heterobimetallic complexes is an attractive strategy for modulation of metal-centered redox chemistry, but quantification of the consequences of incorporating strongly Lewis acidic trivalent cations has received little attention. Here, a family of seven heterobimetallic complexes that pair a redox-active nickel center with La, Y, Lu, Sr, Ca, K, and Na (in the form of their triflate salts) have been prepared on a heteroditopic ligand platform to understand how chemical behavior varies across the comprehensive series. Structural data from X-ray diffraction analysis demonstrate that the positions adopted by the secondary cations in the crown-ether-like site of the ligand relative to nickel are dependent primarily on the secondary cations' ionic radii and that the triflate counteranions are bound to the cations in all cases.

Fertility Knowledge and Educational Experiences of Graduating Medical Students: A Multi-Institution Survey.

Our goal was to assess the fertility knowledge and educational experiences of graduating U.S. medical students to evaluate areas of improvement for future educational interventions.

Synthesis, Isolation, and Study of Heterobimetallic Uranyl Crown Ether Complexes.

Although crown ethers can selectively bind many metal cations, little is known regarding the solution properties of crown ether complexes of the uranyl dication, UO. Here, the synthesis and characterization of isolable complexes in which the uranyl dication is bound in an 18-crown-6-like moiety are reported. A tailored macrocyclic ligand, templated with a Pt(II) center, captures UO in the crown moiety, as demonstrated by results from single-crystal X-ray diffraction analysis.

Reassessing the impact of letrozole co-administration in controlled ovarian hyperstimulation: findings from a single-center repeated measures study.

Purpose: To explore whether letrozole improved outcomes in subsequent controlled ovarian hyperstimulation (COH) cycles.

Methods: This was a retrospective repeated measures cohort study examining COH cycles. Patients were included if they underwent two cycles for unexplained infertility, male factor infertility, or planned oocyte/embryo cryopreservation.

Mechanistic Basis of Conductivity in Carbon Dioxide-Expanded Electrolytes: A Joint Experimental-Theoretical Study.

Electrolyte conductivity contributes to the efficiency of devices for electrochemical conversion of carbon dioxide (CO) into useful chemicals, but the effect of the dissolution of CO gas on conductivity has received little attention. Here, we report a joint experimental-theoretical study of the properties of acetonitrile-based CO-expanded electrolytes (CXEs) that contain high concentrations of CO (up to 12 M), achieved by CO pressurization. Cyclic voltammetry data and paired simulations show that high concentrations of dissolved CO do not impede the kinetics of outer-sphere electron transfer but decrease the solution conductivity at higher pressures.

Live birth rates in in vitro fertilization cycles with five or fewer follicles.

Purpose: To evaluate live birth rates (LBRs) for in vitro fertilization (IVF) cycles with ≤5 follicles at trigger, with the goal of helping patients with low follicle counts decide whether to proceed to retrieval.

Methods: This is a retrospective cohort study from an urban, university-affiliated fertility center. All IVF cycles that yielded <10 oocytes between 2016 and 2020 were reviewed.

Experiences and intentions of patients undergoing medically indicated oocyte or embryo cryopreservation: a qualitative study.

Study Question: What structural (logistical) and psychological challenges do patients who cryopreserve oocytes or embryos for medical reasons face, including possible barriers to using their frozen materials?

Summary Answer: The majority of women who underwent oocyte or embryo cryopreservation for medical reasons reported a desire to use their frozen oocytes or embryos but had been impeded by ongoing medical issues, the need for a gestational carrier, or the lack of a partner.

What Is Known Already: Current data suggest that many women who have frozen oocytes or embryos for medical indications are concerned about the prospect of infertility and have unique emotional and financial needs that differ from patients with infertility. Further, most patients have not returned to use their cryopreserved materials.

Evidence for Uranium(VI/V) Redox Supported by 2,2'-Bipyridyl-6,6'-dicarboxylate.

The 2,2'-bipyridyl-6,6'-dicarboxylate ligand () has been shown in prior work to effectively capture the uranyl(VI) ion, UO, from aqueous solutions. However, the redox properties of the uranyl complex of this ligand have not been addressed despite the relevance of uranium-centered reduction to the nuclear fuel cycle and the presence of a bipyridyl core in , a motif long recognized for its ability to support redox chemistry. Here, the complex of UO () has been synthetically prepared and isolated under nonaqueous conditions for the study of its reductive chemical and electrochemical behavior.

Evaluation of pre-implantation genetic testing for aneuploidy outcomes in patients without infertility undergoing in vitro fertilization compared to infertile controls.

Purpose: To evaluate pre-implantation genetic testing for aneuploidy (PGT-A) outcomes in patients without infertility compared to infertile patients.

Methods: We performed a retrospective cohort study of all patients without an infertility diagnosis ("fertile" patients) who utilized PGT-A at a large university-affiliated fertility center between 2016 and 2021. Fertile patients were 1-to-3 matched to infertile controls by age and number of oocytes retrieved.

Preimplantation genetic testing for monogenic disorders: clinical experience with BRCA1 and BRCA2 from 2010-2021.

Purpose: Our aim was to describe the reproductive decisions and outcomes of BRCA-positive patients who used preimplantation genetic testing for monogenic disorders (PGT-M).

Methods: We performed a retrospective case series of all PGT-M cycles for BRCA variants between 2010-2021 at a large urban academic fertility center. All patients who underwent ≥ 1 cycle of IVF with PGT-M for BRCA1 or BRCA2 were included.

Computational Insights into the Influence of Ligands on Hydrogen Generation with [Cp*Rh] Hydrides.

This work reports a computational investigation of the effect of ancillary ligands on the activity of an Rh catalyst for hydrogen evolution based on the [Cp*Rh] motif (Cp* = η-pentamethylcyclopentadienyl). Specifically, we investigate why a bipyridyl (bpy) ligand leads to H generation but diphenylphosphino-based (dpp) ligands do not. We compare the full ligands to simplified models and systematically vary structural features to ascertain their effect on the reaction energy of each catalytic step.

A balancing act: sex selection after pre-implantation genetic testing for aneuploidy for first versus second baby.

Study Question: How often do patients undergoing frozen embryo transfer (FET) after preimplantation genetic testing for aneuploidy (PGT-A) choose to select for sex and do sex selection rates differ before and after successful delivery of a first baby?

Summary Answer: When a choice was available between male and female embryos, patients selected the sex more frequently when trying to conceive the second child (62%) as compared to the first child (32.4%) and most commonly selected for the opposite sex of the first child.

What Is Known Already: Sex selection is widely available in US fertility clinics.