Pik Ying Chan

Transient-Resonance Raman and Density Functional Theory Investigation of 4-Biphenylylnitrenium, 2-Fluorenylnitrenium, and Diphenylnitrenium Ions

We present transient-resonance Raman spectra for the 4-biphenylylnitrenium, diphenylnitrenium, and 2-fluorenylnitrenium ions. These spectra display a number of fundamental vibrational bands whose frequencies exhibit good agreement with those computed using BPW91/cc-PVDZ density functional theory calculations for the singlet ground states of the 4-biphenylylnitrenium, diphenylnitrenium, and 2-fluorenylnitrenium ions. Comparison of these arylnitrenium ions with each other and with previous results for structurally similar biphenyl radical cations indicates that the degree of iminocyclohexadienyl character observed in these arylnitrenium ions depends on the relative orientation of the two phenyl rings, the nature of the nitrenium ion moiety, and the ability of the biphenyl-like group to accommodate positive charge through formation of a more planar-like structure with quinoidal-like character.

Transient resonance Raman and density functional theory study of the 7-bromo-2-fluorenylnitrenium cation

We report the first transient resonance Raman spectra for a halogen-substituted arylnitrenium ion, the 7-bromo-2-fluorenylnitrenium ion. The Raman band vibrational frequencies were found to be in good agreement with those predicted from density functional theory calculations for the singlet state of the 7-bromo-2-fluorenylnitrenium ion but not very well for the triplet state, particularly for the diagnostic 1530 cm−1 to 1650 cm−1 aromatic C=C stretch modes. This and the predicted 23.7 kcal/mol singlet-triplet energy gap with the singlet state being more stable indicates the transient resonance Raman spectra are due mainly to the singlet 7-bromo-2-fluorenylnitrenium ion. Comparison of the structures and properties of the 7-bromo-2-fluorenylnitrenium ion to the closely related 2-fluorenylnitrenium ion previously studied shows the 7-bromo substituent does not significantly perturb the iminocyclohexadienyl character of the 2-fluorenyl moiety and the structure of the first phenyl ring. However, the 7-bromo substituent does noticeably influence the structure of the second phenyl ring to which it is attached and also the normal mode character of a number of lower frequency modes with relatively delocalized character.

Metabolic screening for patients with second-generation antipsychotic medication: A population-based study from 2004 to 2016

Patients with severe mental disorders have excess mortality due to preventable physical diseases, especially cardiovascular disease (Crump et al., 2013). One of the major risk factors for cardiovascular diseases is metabolic syndrome (Kaur, 2014), yet it has been reported that the prevalence for patients to develop metabolic syndrome doubles that of the general population (Riordan et al., 2011). A link between second-generation antipsychotic medications and the increased risk for both metabolic and cardiovascular abnormalities has been proposed (De Hert et al., 2012). Previous study focused on glucose and lipid level has even reported that antipsychotic-treated patients had more glucose and lipid metabolic abnormalities than drug-naïve patients with schizophrenia (Wu et al., 2014). Monitoring for potential side effects of antipsychotics is thus important. Guidelines for tracking the metabolic side-effects from antipsychotics have been proposed before, but the metabolic screening procedures proposed still remain underutilized (Barnes et al., 2015; De Hert et al., 2011; Morrato et al., 2016). Use of antipsychotic medication has been increasing in the Chinese population in the recent decade (Lee et al., 2016), it is therefore crucial to understand the current situation of metabolic screening for patients prescribed with second-generation antipsychotic medication. We report the principal findings of the trend of metabolic screening from a population-based study, comprising 525,904 personyears over a 13-year period. Data on antipsychotic prescriptions and metabolic screening in Hong Kong were derived from the Clinical Data Analysis and Reporting System (CDARS), which has been used in the previous study (Lee et al., 2016). Rates of metabolic screening in each age group were calculated as the number of metabolic screening divided the people with second-generation antipsychotic medication (Fig. 1). Proportion of glucose testing increased from 38.5% in 2004 to 57.6% in 2016 (RR, 1.50; 95% CI, 1.46–1.53; P b 0.001) and proportion of lipids testing increased from 11.3% in 2004 to 47.5% in 2016 (RR, 4.21; 95% CI, 4.00–4.42; P b 0.001). In 2016, the proportion of glucose testing was higher than the proportion of lipids testing (70.1% vs 48.5% in 2016; P b 0.001). Higher age was associated with higher