No abstract

It was observed that the relative position of the arene substituents have a profound influence on the strength of π-π stacking in the 9-benzyl substituted triptycene system. A new series of model compounds (3a-i) capable of revealing quantitatively π-π stacking interactions was studied. This series of compounds (3a-i) has an ortho substituted methyl group in one of the two interacting arenes and the syn/anti ratios were determined and compared to a series previously studied compounds (4a-i) that have a para methyl group on the corresponding arene. A greater than 50% increase in the strength of π-π stacking interactions was observed with the methyl group in the ortho position comparing to that in the para position. No difference in π-π stacking interactions was observed when the other aromatic ring was a pentafluorobenzoate group.Noncovalent interactions play an increasingly important role in modern chemical research. [1][2][3] The concept of π-stacking interactions has been used in a wide ranging field of science including materials science, 4 template-directed synthesis, 5 and enzyme design. 6 Currently there is a strong interest to understand the origins and the mechanism of substituent effects in π-π stacking interactions. [7][8][9] It has been reported that a direct interaction between the aromatic ring hydrogens and the substituents themselves may influence the magnitude of arene-arene interaction. 10 Theoretical studies also corroborated this observation using benzene dimers with multiple substituents. The substituent effects were found to be nearly additive in sandwich configurations, which would not be consistent with the traditional model of aromatic substituent effects. 8 More recently, computational studies by Wheeler and Houk directly challenged the conventional concept of substituent effects. 7 Their study suggests that substituents interact directly with another aromatic ring, rather than through the polarization of the arene. According to this study, the traditional concept of π-π interactions tuned by substituents through electron withdrawing or donating to the aromatic rings is flawed and should be corrected by direct interactions between the substituents and the unsubstituted ring. In this communication, we report experimental observations which show the relative position of the arene substituents has a Correspondence to: Benjamin W. Gung. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public Access NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript strong influence on π-π stacking strength, thus suggesting a direct i...

Background: Despite improved insurance coverage for gender confirmation surgeries in the United States, coverage for facial feminization surgery (FFS) continues to be difficult. Here, we describe our institutional experience on navigation, time, and costs of the FFS insurance authorization process. Methods: FFS consults (n = 40) at the University of California, Los Angeles (2018–2020) were reviewed for time and cost to definitive insurance authorization decision. Patients were stratified into 3 groups based on authorization process: Group A (standard approval, n = 26, 65.0%) including public and private insurances; Group B (extended approval, n = 10, 25.0%) consisting of private insurance plans that initially denied and required multi-level appeals for denial overturn; and Group C (denial, n = 4, 10.0%), including private insurance plans that denied even after multi-level appeals. Results: An estimated 90% of all patient consults were approved for FFS under insurance. Group A averaged 1.1 months for approval, requiring 1.4 hours of administrative time translating to $38.18 per patient. The addition of multi-level appeals in Groups B and C increased the total time for a definitive decision (7.0 and 5.1 months, respectively) and required both surgeon and administrative time to navigate the process (10.8 and 12.0 hours, respectively). The time spent on the presurgical authorization process for Groups B and C translated to an over 20-fold increase in cost ($855.00 and $988.38, respectively) compared with Group A. Conclusion: Navigation of the insurance process for FFS is challenging and time-consuming; however, coverage is a reality in California provided that multi-level appeals are exhausted.

Facial feminization surgery (FFS) incorporates aesthetic and craniofacial surgical principles and techniques to feminize masculine facial features and facilitate gender transitioning. A detailed understanding of the defining male and female facial characteristics is essential for success. In this first part of a two-part series, we discuss key aspects of the general preoperative consultation that should be considered when evaluating the prospective facial feminization patient. Assessment of the forehead, orbits, hairline, eyebrows, eyes, and nose and the associated procedures, including scalp advancement, supraorbital rim reduction, setback of the anterior table of the frontal sinus, rhinoplasty, and soft tissue modifications of the upper and midface are discussed. In the second part of this series, bony manipulation of the midface, mandible, and chin, as well as soft tissue modification of the nasolabial complex and chondrolaryngoplasty are discussed. Finally, a review of the literature on patient-reported outcomes in this population following FFS is provided.

Facial feminization surgery (FFS) refers to a set of procedures aimed at altering the features of a masculine face to achieve a more feminine appearance. In the second part of this twopart series, assessment and operations involving the midface, mandible, and chin, as well as soft tissue modification of the nasolabial complex and chondrolaryngoplasty, are discussed. Finally, we provide a review of the literature on patient-reported outcomes in this population following FFS and suggest a path forward to optimize care for FFS patients.