Why PEDOT:PSS Should Not Be Used for Raman Sensing of Redox States (and How It Could Be)

Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) has been recently proposed for Raman sensing of redox-active species in solution. Here, we investigated the rationale of this approach through systematic experiments, in which the Raman spectrum of PEDOT:PSS was analyzed in the presence of either nonoxidizing or oxidizing electrolytes. The results demonstrated that Raman spectra precisely reflect the conformation of PEDOT units and their interactions with PSS. Two different responses were observed. In the case of oxidizing electrolytes, the effect of charge transfer is accurately transduced in Raman spectrum changes. On the other hand, reduction induces a progressive separation between the PEDOT and PSS chains, which decreases their mutual interaction. This stimulus determines characteristic variations in the intensity, shape, and position of the Raman spectra. However, we demonstrated that the same effects can be obtained either by increasing the concentration of nonoxidizing electrolytes or by deprotonating PSS chains. This poses severe limitations to the use of PEDOT:PSS for this type of Raman sensing. This study allows us to revise most of the Raman results reported in the literature with a clear model, setting a new basis for investigating the dynamics of mixed electronic/ionic charge transfer in conductive polymers

More than Body Appearance (MBA): A randomized controlled trial aimed to promote a positive body image in young females with body dissatisfaction

Objective: Positive body image may represent a protective factor for the development of Eating Disorders (Piran, 2015). The aim of the study was to test the efficacy of an online psychological intervention (More Than Body Appearance, MBA) focused on body functionality appreciation (i.e., a facet of positive body image) in enhance positive body image and reduce body dissatisfaction in young females with body dissatisfaction. Method: Forty-seven females (Mage = 21.81) who scored above the clinical cut-off on a self-report questionnaire assessing body dissatisfaction were randomized into two groups: experimental group (n = 24) and waiting-list group (n = 23). The experimental group started the intervention at baseline (T0) for 15 consecutive days (until T1). The waiting-list group waited for 15 days before starting the intervention (T1 to T2). Participants completed questionnaires about body dissatisfaction (i.e., Questionario sul Dismorfismo Corporeo, QDC) and positive body image (i.e., Functionality Appreciation Scale, FAS; Body Appreciation Scale-2, BAS-2) at baseline (T0), 15 days from baseline (T1), and 30 days from baseline (T2). Results: Repeated measure Analyses of Variances (ANOVAs) showed Group (experimental vs. waiting-list) × Time (T0 vs. T1) interactions on QDC (p = .04), FAS (p < .001), and BAS-2 (p = .01), indicating a greater decrease in body dissatisfaction and an increase in positive body image in the experimental group compared to the waiting-list group at T1. Discussion: A 15-days online psychological intervention focused on functionality appreciation may enhance positive body image and reduce body dissatisfaction in young females with body dissatisfaction

Why PEDOT:PSS Should Not Be Used for Raman Sensing of Redox States (and How It Could Be)

Here we investigated the rationale of this approach through systematic experiments, in which the Raman spectrum of PEDOT:PSS was analyzed in the presence of either non-oxidizing and oxidizing electrolytes. The results demonstrated that Raman spectra precisely reflect the conformation of PEDOT units and their interactions with PSS. Two different responses were observed. In the case of oxidizing electrolytes, the effect of charge transfer is accurately transduced in Raman spectrum changes. On the other hand, reduction induces a progressive separation between the PEDOT and PSS chains, which decreases their mutual interaction. This stimulus determines characteristic variations in intensity, shape and position of the Raman spectra. However, we demonstrated that the same effects can be obtained either by increasing the concentration of non-oxidizing electrolytes or by deprotonating PSS chains. This poses severe limitations to the use of PEDOT:PSS for this type of Raman sensing. This study allows to revise most of the Raman results reported in literature with a clear model, setting a new basis for investigating the dynamics of mixed electronic/ionic charge transfer in conductive polymers

Physicochemical Characterization of Hydroxyapatite Hybrids with Meloxicam for Dissolution Rate Improvement

Organic–inorganic hybrids represent a good solution to improve the solubility and dissolution rates of poorly soluble drugs whose number has been increasing in the last few years. One of the most diffused inorganic matrices is hydroxyapatite (HAP), which is a biocompatible and osteoconductive material. However, the understanding of the hybrids’ functioning mechanisms is in many cases limited; thus, thorough physicochemical characterizations are needed. In the present paper, we prepared hybrids of pure and Mg-doped hydroxyapatite with meloxicam, a drug pertaining to the Biopharmaceutical Classification System (BCS) class II, i.e., drugs with low solubility and high permeability. The hybrids’ formation was demonstrated by FT-IR, which suggested electrostatic interactions between HAP and drug. The substitution of Mg in the HAP structure mainly produced a structural disorder and a reduction in crystallite sizes. The surface area of HAP increased after Mg doping from 82 to 103 m2g−1 as well as the pore volume, justifying the slightly high drug amount adsorbed by the Mg hybrid. Notwithstanding the low drug loading on the hybrids, the solubility, dissolution profiles and wettability markedly improved with respect to the drug alone, particularly for the Mg doped one, which was probably due to the main distribution of the drug on the HAP surface