Charge Density Study of Two-Electron Four-Center Bonding in a Dimer of Tetracyanoethylene Radical Anions as a Benchmark for Two-Electron Multicenter Bonding.

The dimer of the tetracyanoethylene (TCNE) radical anions represents the simplest and the best studied case of two-electron multicenter covalent bonding (2e/mc or ). The model compound, -methylpyridinium salt of TCNE, is diamagnetic, meaning that the electrons in two contiguous radicals are paired and occupy a HOMO orbital which spans two TCNE radicals. Charge density in this system is studied as a benchmark for comparison of charge densities in other pancake-bonded radical systems.

Comparison of Percutaneous Internal Ring Suturing (PIRS) versus Open Ligation of the Patent Processus Vaginalis for the Treatment of Communicating Pediatric Hydrocele.

Background: Although the laparoscopic approach become standard for the treatment of many surgical conditions many studies still debating whether laparoscopic surgery has significant advantages over open surgery in regards to hernia or hydrocele treatment. This study aimed to evaluate the outcomes of treatment of treatment of communicating hydrocele in pediatric patients between laparoscopic percutaneous internal ring suturing (PIRS) and open ligation of the patent processus vaginalis (PPV).

Methods: The medical records of pediatric patients who underwent surgery for communicating hydrocele between 1 January 2019 and 1 January 2024 were retrospectively reviewed.

Selenocyclization by Formation of Carbon-nitrogen Bonds.

Selenium promoted-cyclization of unsaturated substrates containing internal nitrogen nucleophiles, such as different amines and amides, including the examples of its application in the synthesis of more complex polycyclic compounds is reviewed. Selenocyclization reactions of some more specific polyfunctional substrates, like Biginelli hybrids and hydantoins, are also covered.

Influence of human embryo cultivation in a classic CO2 incubator with 20% oxygen versus benchtop incubator with 5% oxygen on live births: the randomized prospective trial.

SummaryOur objective was to assess the effect of benchtop incubators with low oxygen concentrations on the clinical and embryological parameters of our patients. We conducted a prospective, randomized, opened controlled trial on infertile patients in stimulated cycles. In total, 738 infertile patients were assessed for eligibility and, after final exclusions, 230 patients were allocated either to a 5% O2 group (benchtop incubator) or a 20% O2 group (classic incubator).

Current Preventive Strategies for Preovulatory Progesterone Elevation During Ovarian Stimulation for In Vitro Fertilization.

The purpose of this review is to present contemporary measures for preventing the increase in preovulatory progesterone (P) and its adverse effects on ovarian stimulation in in vitro fertilization (IVF). For the last 20 years, the increase of preovulatory P has been a topic of numerous discussions because its role is not fully understood in terms of its impact on pregnancy outcome after IVF. Some studies failed to establish a connection between the preovulatory P increase and successful IVF outcome regardless of the level of P, while, conversely, most other studies have reported on adverse effects of elevated P concentrations.