Refractive index of nanoconfined water reveals its anomalous physical properties

Despite extensive studies on the distinctive properties of water confined in a nanospace, the underlying mechanism and significance of the lengthscale involved in the confinement effects are still subjects of controversy. The dielectric constant and the refractive index in particular are key parameters in modeling and understanding nanoconfined water, yet experimental evidence is lacking. We report the measurement of the refractive indices of water in 10-100 nm spaces by exploiting the confinement of water and localized surface plasmons in a physicochemically well-defined nanocavity. The results revealed significantly low values and the scaling behavior of the out-of-plane refractive index n⊥ of confined water. They are attributed to the polarization suppression at the interfaces and the long-range correlation in electronic polarization facilitated by the strengthened H-bonding network. Using the refractive index as a sensing probe, we also observed anomalous stability of water structures over a wide range of temperature. Our measurement results provide essential feedback information for benchmarking water models and molecular interactions under nanoconfinement. This study also opens up a new methodology of using plasmon resonance in characterizing nanoconfined molecules and chemical reactions, and thus gives us fundamental insight into confinement effects.

Efficacy of guselkumab in a subpopulation with pustulotic arthro-osteitis through week 52: an exploratory analysis of a phase 3, randomized, double-blind, placebo-controlled study in Japanese patients with palmoplantar pustulosis

Background

Previous studies of guselkumab have demonstrated clinical benefits in patients with plaque‐type psoriasis, generalized pustular psoriasis, erythrodermic psoriasis and palmoplantar pustulosis (PPP).

Objective

The aim of this exploratory analysis of a double‐blind, multicenter, placebo‐controlled, phase 3 study in Japanese patients with PPP was to evaluate the efficacy of guselkumab in the subset of patients with pustulotic arthro‐osteitis (PAO).

Methods

Patients were randomized to receive guselkumab 100 or 200 mg at weeks 0, 4, 12 and every 8 weeks, or placebo with cross‐over to guselkumab 100 or 200 mg at week 16 (placebo group). Efficacy endpoints were changes from baseline in magnetic resonance imaging (MRI) score, EuroQOL‐5 dimensions (EQ‐5D) index score, EQ‐5D pain/discomfort dimension score and C‐reactive protein (CRP, mg/L) level in all PAO patients through week 52. Data from both guselkumab groups were combined and presented as results for a single overall guselkumab group.

Results

Among 159 patients with PPP, 66 with PAO were randomized across treatment groups. For patients with MRI data for all regions assessed, the proportion of patients in the guselkumab group with PAO characterized as severe decreased from 23.8% (10/42) at baseline to 5.4% (2/42) at week 52. The mean (SD) change from baseline at week 52 in EQ‐5D index score was 0.20 (0.17) among PPP patients with PAO and 0.15 (0.17) among those without PAO in the guselkumab group. Among all PAO patients, the proportions with an EQ‐5D pain/discomfort dimension score of no or slight pain/discomfort in the guselkumab group increased from baseline to week 52 [33.3% (7/21) vs. 87.5% (35/40)]. The mean (SD) CRP levels decreased in all PAO patients in the guselkumab group at week 52 compared to baseline [−1.71 (8.16) mg/L].

Conclusion

Guselkumab treatment showed beneficial outcomes for PAO signs and symptoms in Japanese patients with PPP.

Ixekizumab treatment improves fingernail psoriasis in patients with moderate-to-severe psoriasis: results from the randomized, controlled and open-label phases of UNCOVER-3

BACKGROUND

Fingernail psoriasis is difficult to treat.

OBJECTIVE

The objective was to evaluate the effect of ixekizumab, a monoclonal antibody selectively targeting IL-17A, on fingernail psoriasis.

METHODS

This Phase 3, double-blind trial (UNCOVER-3) randomized patients to placebo, etanercept (50-mg twice weekly), or 80 mg ixekizumab as one injection every 4 (IXE Q4W) or 2 weeks (IXE Q2W) after a 160-mg starting dose. At Week 12, ixekizumab patients received open-label IXE Q4W through Week 60; placebo patients received a 160-mg starting ixekizumab dose and etanercept patients a 4-week placebo washout before starting IXE Q4W. Efficacy was assessed by mean per cent Nail Psoriasis Severity Index (NAPSI) improvement at Weeks 12 and 60.

RESULTS

Of 1346 patients in the UNCOVER-3 trial, this subgroup analysis included only patients with baseline fingernail psoriasis: 116 (60.1%) placebo, 236 (61.8%) etanercept, 228 (59.1%) IXE Q4W and 229 (59.5%) IXE Q2W. At Week 12, greater mean per cent NAPSI improvements were achieved in IXE Q4W (36.7%) and IXE Q2W (35.2%) vs. placebo (-34.3%, P < 0.001 each comparison) and etanercept (20.0%, P = 0.048 vs. Q4W, P = 0.072 vs. Q2W). At Week 60, mean per cent NAPSI improvement was >80% regardless of initial treatment. At Week 12 (nonresponder imputation), complete resolution (NAPSI = 0) was achieved in 19.7% (IXE Q4W), 17.5% (IXE Q2W), 4.3% (placebo, P < 0.001 each comparison) and 10.2% (etanercept, P < 0.05 each comparison) of patients. By Week 60, >50% of patients achieved complete resolution.

CONCLUSIONS

At Week 12, significant improvements in fingernail psoriasis were achieved with ixekizumab therapy. With IXE Q4W maintenance dosing, additional improvement was demonstrated through 60 weeks, and >50% of patients achieved complete resolution. Registered at clinicaltrials.gov: NCT01646177.