On Relationships between Gas-Phase Chemistry and Reactive Ion Etching Kinetics for Silicon-Based Thin Films (SiC, SiO2 and SixNy) in Multi-Component Fluorocarbon Gas Mixtures

This work summarizes the results of our previous studies related to investigations of reactive ion etching kinetics and mechanisms for widely used silicon-based materials (SiC, SiO2, and SixNy) as well as for the silicon itself in multi-component fluorocarbon gas mixtures. The main subjects were the three-component systems composed either by one fluorocarbon component (СF4, C4F8, CHF3) with Ar and O2 or by two fluorocarbon components with one additive gas. The investigation scheme included plasma diagnostics by Langmuir probes and model-based analysis of plasma chemistry and heterogeneous reaction kinetics. The combination of these methods allowed one (a) to figure out key processes which determine the steady-state plasma parameters and densities of active species; (b) to understand relationships between processing conditions and basic heterogeneous process kinetics; (c) to analyze etching mechanisms in terms of process-condition-dependent effective reaction probability and etching yield; and (d) to suggest the set gas-phase-related parameters (fluxes and flux-to-flux ratios) to control the thickness of the fluorocarbon polymer film and the change in the etching/polymerization balance. It was shown that non-monotonic etching rates as functions of gas mixing ratios may result from monotonic but opposite changes in F atoms flux and effective reaction probability. The latter depends either on the fluorocarbon film thickness (in high-polymerizing and oxygen-less gas systems) or on heterogeneous processes with a participation of O atoms (in oxygen-containing plasmas). It was suggested that an increase in O2 fraction in a feed gas may suppress the effective reaction probability through decreasing amounts of free adsorption sites and oxidation of surface atoms.

Rosuvastatin induced gynecomastia: a rare presentation of newer statin

Gynecomastia is a common benign disease characterized by the progressive enlargement of the glandular tissue of the male breast. The etiology may vary and may be physiological, pharmacological, pathological, or even idiopathic. Among men, drug induced gynecomastia may account for 10-20% of cases. Several case reports have associated this condition to the use of statins. However, there are few case reports of rosuvastatin induced gynecomastia have been reported in literature. We describe a 45-year-old male who developed bilateral gynecomastia after one month of rosuvastatin therapy, after switching to a different or less potent statin (atorvastatin), his symptoms resolved with-in one month. Use of the Naranjo adverse drug reaction probability scale indicated a possible relationship between the patient’s development of gynecomastia and rosuvastatin therapy.

Carbonation dysgeusia associated with topiramate

Purpose A case of carbonation dysgeusia associated with the use of topiramate is reported in order to bring awareness to a lesser-known adverse effect of the medication so that providers may be able to more effectively counsel patients and provide potential solutions. Summary A 39-year-old Caucasian woman with longstanding epilepsy was initiated on topiramate therapy after experiencing a generalized seizure (she reported not taking any antiepileptic medication for years). Topiramate was started at a dosage of 25 mg by mouth twice daily and after 3 weeks titrated to a dosage of 100 mg by mouth twice daily for maintenance therapy. After initiation of topiramate therapy, the patient began to experience an immediate change in her carbonation perception when drinking carbonated beverages; all carbonated beverages, including seltzer and beer, tasted “flat.” The patient remained on topiramate for the subsequent 12 months without her carbonation perception returning to normal but noted that drinking carbonated beverages through straws slightly mitigated the adverse effect. Case assessment using the adverse drug reaction probability scale of Naranjo et al indicated that topiramate was the probable cause of the patient’s carbonation taste perversion. Conclusion A 39-year-old Caucasian woman developed chronic carbonation dysgeusia after initiation of topiramate following a generalized seizure.

Reduced-Dimensionality Quantum Dynamics Study of the 3Fe(CO)4 + H2 → 1FeH2(CO)4 Spin-inversion Reaction

Many chemical reactions of transition metal compounds involve a change in spin state via spin inversion, which is induced by relativistic spin-orbit coupling. In this work, we theoretically study the efficiency of a typical spin-inversion reaction, 3Fe(CO)4 + H2 → 1FeH2(CO)4. Structural and vibrational information on the spin-inversion point, obtained through the spin-coupled Hamiltonian approach, is used to construct three degree-of-freedom potential energy surfaces and to obtain singlet-triplet spin-orbit couplings. Using the developed spin-diabatic potential energy surfaces in reduced dimensions, we perform quantum nonadiabatic transition state wave packet calculations to obtain the cumulative reaction probability. The calculated cumulative reaction probability is found to be significantly larger than that estimated from the one-dimensional surface-hopping probability. This indicates the importance of both multidimensional and nuclear quantum effects in spin inversion for polyatomic chemical reaction systems.

Microscopic characteristics of Janus nanoparticles prepared via a grafting-from reaction at the immiscible liquid interface

The interfacial tension, initial monomer concentration, and reaction probability can greatly influence the microscopic characteristics of the Janus nanoparticle (JNP) structure. The asymmetric initial monomer concentration in solution and the reaction probability can be used to control the syntheses of asymmetric JNPs.

Reaction probability and kinetics of water splitting on the penta-NiAs2 monolayer from an ab initio molecular dynamics investigation

The reaction probability and kinetics of the water splitting process on the penta-NiAs2 monolayer are studied using ab initio molecular dynamics simulations.