In vitro fertilization-embryo transfer in patients with unexplained recurrent pregnancy loss.

BACKGROUND: Empiric therapy for patients with unexplained recurrent pregnancy loss (URPL) is not precise. Some patients will ask for assisted reproductive technology due to secondary infertility or advanced maternal age. The clinical outcomes of URPL patients who have undergone in vitro fertilization-embryo transfer (IVF-ET) require elucidation. The IVF outcome and influencing factors of URPL patients need further study. METHODS: A retrospective cohort study was designed, and 312 infertile patients with URPL who had been treated during January 2012 to December 2015 in the Reproduction Center of Peking University Third Hospital were included. By comparing clinical outcomes between these patients and those with tubal factor infertility (TFI), the factors affecting the clinical outcomes of URPL patients were analyzed. RESULTS: The clinical pregnancy rate (35.18% vs. 34.52% in fresh ET cycles, P = 0.877; 34.48% vs. 40.27% in frozen-thawed ET cycles, P = 0.283) and live birth rate (LBR) in fresh ET cycles (27.67% vs. 26.59%, P = 0.785) were not significantly different between URPL group and TFI group. URPL group had lower LBR in frozen-thawed ET cycles than that of TFI group (23.56% vs. 33.56%, P = 0.047), but the cumulative LBRs (34.69% vs. 38.26%, P = 0.368) were not significantly different between the two groups. The increased endometrial thickness (EMT) on the human chorionic gonadotropin day (odds ratio [OR]: 0.848, 95% confidence interval [CI]: 0.748-0.962, P = 0.010) and the increased number of eggs retrieved (OR: 0.928, 95% CI: 0.887-0.970, P = 0.001) were protective factors for clinical pregnancy in stimulated cycles. The increased number of eggs retrieved (OR: 0.875, 95% CI: 0.846-0.906, P < 0.001), the increased two-pronucleus rate (OR: 0.151, 95% CI: 0.052-0.437, P < 0.001), and increased EMT (OR: 0.876, 95% CI: 0.770-0.997, P = 0.045) in ET day were protective factors for the cumulative live birth outcome. CONCLUSION: After matching ages, no significant differences in clinical outcomes were found between the patients with URPL and the patients with TFI. A thicker endometrium and more retrieved oocytes increase the probability of pregnancy in fresh transfer cycles, but a better normal fertilization potential will increase the possibility of a live birth.

Coordination templated [2+2+2] cyclotrimerization in a porous coordination framework.

Controlling chemical reactions by the supramolecular confinement effects of nanopores has attracted great attention. Here we show that open metal sites in porous coordination frameworks can constitute more powerful and strict templates for precision syntheses. A Fe(III) dicarboxylate framework functionalized with triangularly arranged metal sites is used to accomplish [2+2+2] cyclotrimerization reactions for organonitrile, alkyne and alkene monomers bearing a geometrically suitable pyridyl group. In situ single-crystal X-ray diffraction facilitates the direct observation of such a coordination templated reaction, before cylcotrimerization, the monomer coordinates at the Fe(III) centre by its pyridyl donor, which forces three unsaturated groups to gather around a position very similar with that of the desired covalent cyclic trimer. After the reaction, the trimers serve as tripodal ligands to perfectly fix the Fe(III) ions and the whole crystal to generate an exceptionally rigid and porous material with large surface area coupled with guest-proof zero thermal expansion.

Tuning fluorocarbon adsorption in new isoreticular porous coordination frameworks for heat transformation applications.

Adsorption heat transformation is one of the most energy-efficient technologies, which relies much on the type and performance of the adsorbent-adsorbate pair. Here, we report adsorption behaviors of a typical fluorocarbon R22 (CHClF2) in a new series of isoreticular porous coordination polymers [Zn4O(bpz)2(ldc)], in which the typical Zn4O clusters are connected by hydrophobic 3,3',5,5'-tetramethyl-4,4'-bipyrazolate (bpz2-) and different linear dicarboxylates (ldc2-) to form non-interpenetrated pcu networks with variable pore sizes, shapes, and volumes. Fluorocarbon sorption measurements of these materials revealed high R22 uptakes of 0.73-0.97 g g-1 (0.62-0.65 g cm-3) at 298 K and 1 bar and working capacities of 0.41-0.72 g g-1 (0.35-0.47 g cm-3) between 273 and 313 K at about 0.13, 0.11 and 0.52 bar, respectively, as well as very large diffusion coefficients of 5.1-7.3 × 10-7 cm2 s-1. Noteworthily, the R22 sorption performance can be dramatically improved by subtle modification of the pore size and shape, demonstrating porous coordination polymer-fluorocarbon as a promising adsorbent-adsorbate pair for heat transformation applications.