No abstract

No abstract

Recent ab initio theoretical calculations of the electrical performance of several two-dimensional materials predict a low-field carrier mobility that spans several orders of magnitude (from 26,000 to 35 cm 2 V −1 s −1 , for example, for the hole mobility in monolayer phosphorene) depending on the physical approximations used. Given this state of uncertainty, we review critically the physical models employed, considering phosphorene, a group V material, as a specific example. We argue that the use of the most accurate models results in a calculated performance that is at the disappointing lower-end of the predicted range. We also employ first-principles methods to study high-field transport characteristics in mono-and bi-layer phosphorene. For thin multi-layer phosphorene we confirm the most disappointing results, with a strongly anisotropic carrier mobility that does not exceed ∼ 30 cm 2 V −1 s −1 at 300 K for electrons along the armchair direction.

No abstract

Acne is a very common non-infectious skin condition that is frequently treated in dermatological practices. Because acne is often chronic and may persist for years, safe and effective long-term maintenance therapy is often required. Given the increasing frequency of antibiotic-resistant bacteria and the gravity of the consequences of this trend, it behooves dermatologists to maximize use of non-antimicrobial therapy when treating acne. In this review of the literature we present data regarding the efficacy and appropriate use of non-antimicrobial treatments for acne. A variety of topical and oral treatment options exist that can be used in a step-wise manner according to the patients’ severity and therapeutic response. Non-antimicrobial treatments can be highly efficacious at controlling acne, especially when used as maintenance therapy. While antibiotics have a role in acne treatment, they should not be used as monotherapy, and lengthy courses of antibiotic use are discouraged.

The absolute molecular electronegativities for 14 aromatic hydrocarbons are reported. For the hydrocarbons considered, a linear relationship exists between the electron affinity and the energy of the 1 La transition. The molecular electronegativity for some eight aromatic hydrocarbons is approximately constant. On this basis, it is possible to predict some ionization potentials which are in excellent agreement with recent experimental values. It does not appear reasonable to relate the intercept resulting from extrapolation of the aforementioned plot to hv=O to the work function of graphite. Based on the measured electron affinities, it is possible to deduce a relationship with methyl affinities and calculate toE •• l between neutral hydrocarbons and their mononegative ions. Certain theoretical approaches can be successfully employed to estimate electron affinities of aromatic hydrocarbons.

No abstract

IMPORTANCEWomen with aortopathy conditions are at risk for pregnancy-related aortic dissection, and these conditions may not be recognized until after the aortic dissection occurs.OBJECTIVE To examine the clinical characteristics, imaging features, and outcomes in women with pregnancy-related acute aortic dissection.