Microscopic Investigation on Morphologies of Bilayer Gel Structure in the Mixed Polyoxyethylene-Type Nonionic Surfactant Systems

We investigated morphologies of lamellar domains below the Krafft temperature in the mixed polyoxyethylene-type nonionic surfactant, a C₁₆E₆/C₁₆E₇/water system, by using optical microscopy, confocal microscopy, small/wide-angle X-ray scattering, and small-angle neutron scattering. We have found that the morphology discontinuously changes from network structures of lamellar domains to spherical vesicles with increasing mole fraction of C₁₆E₇, via the coexistence region of vesicles and network structures of lamellar domains

Effects of Oscillatory Shear on the Orientation of the Inverse Bicontinuous Cubic Phase in a Nonionic Surfactant/Water System

The bicontinuous inverse cubic phase (V₂ phase) formed in amphiphilic systems consists of bilayer networks with a long-range order. We have investigated effects of oscillatory shear on the orientation of the V₂ phase with space group <i>Ia</i>3<i>d</i> formed in a nonionic surfactant (C₁₂E₂)/water system by using simultaneous measurements of rheology/small-angle X-ray scattering. It is shown that grain refining occurs by applying the large amplitude oscillatory shear (LAOS) with a strain amplitude (γ₀) of ∼20, which gives the ratio of the loss modulus (<i>G</i>″) to the storage modulus (<i>G</i>′) (<i>G</i>″/<i>G</i>′ = tan δ) of ∼100. On the other hand, orientation of the cubic lattice occurs when the small amplitude (γ₀ ≈ 0.0004) oscillatory shear (SAOS) in the linear regime is applied to the sample just after the LAOS. Interestingly, the orientation is strongly enhanced by the “medium amplitude” (γ₀ ≈ 0.05) oscillatory shear (“MAOS”) after the SAOS. When the MAOS is applied before applying the LAOS, orientation to a particular direction is not observed, indicating that the grain refining process by the LAOS is necessary for the orientation during the MAOS. The results of additional experiments show that the shear sequence “LAOS–MAOS” is effective for the orientation of the cubic lattice. When the LAOS and MAOS are applied to the sample alternatively, grain refining and orientation occur during the LAOS and MAOS, respectively, indicating reversibility of the orientation. It is shown that (i) the degree of the orientation is dependent on γ₀ and the frequency (ω) of the MAOS and (ii) relatively higher orientation can be obtained for the combination of γ₀ and ω, which gives tan δ = 2–3. The lattice constant does not change throughout all the shearing processes and is equal to that before shearing within the experimental errors, indicating that the shear melting does not occur. These results suggest a possibility to control the orientation of the cubic lattice only by changing the conditions of oscillatory shear without using the epitaxial transition from other anisotropic phases, such as the hexagonal and lamellar phases

Electrolyte Effect on Lamellar Domain Morphology in a Nonionic Surfactant Solution below the Krafft Temperature

In our previous papers, we have studied the lamellar domain morphology in aqueous solutions of nonionic surfactants C₁₆E₆ and C₁₆E₇ below the Krafft temperature. In this study, electrolyte effects on lamellar domain morphology have been investigated by means of DSC, confocal microscope, small/wide-angle X-ray scattering (SAXS/WAXS). It has been found that vesicles in C₁₆E₇ solution are transformed to network structures by adding chaotropic ion Cl^–, F^– and CH₃COO^–, whereas the network structures in C₁₆E₆ solution are gradually changed to the vesicles with increasing kosmotropic ion SCN^– concentration. Especially, we focused on the SCN^– ion effects on the C₁₆E₆ system, and found that the characteristic morphology of cylinder-like domains were formed in a certain specific concentration range. In the SAXS observation in nm scale, we have also found that the repeat distance of lamellar structures in the C₁₆E₆/NaSCN solution is anomalously swollen when adding 1.2–2 mol/kg NaSCN, where the cylinder-like domains are formed. We have concluded that the cylindrical vesicles could be explained by the osmotic pressure difference due to the addition of NaSCN

Pressure-Induced Transition of Bilayers in a Nonionic Surfactant Solution

Pressure effects on the bilayers of polyoxyethylene type nonionic surfactant in water have been investigated by means of small- and wide-angle X-ray scattering. It has been found that the Krafft transition from the micellar phase to the lamellar gel phase (L_β) is induced by pressure. By further pressurizing, the lamellar structural parameters, such as the repeat distance <i>d</i> and Caillé parameter η, discontinuously decrease after taking a maximum. All the SAXS and WAXS results revealed that the L_β phase is transformed into the higher-ordered lamellar crystal phase (L_c). On the basis of these observations, we have made the <i>T</i>–<i>C</i> and <i>T</i>–<i>P</i> phase diagrams

Re-entrant Lamellar/Onion Transition with Varying Temperature under Shear Flow

We have found for the first time the reentrant lamellar/onion (lamellar–onion–lamellar) transition with varying temperature under constant shear rate by using simultaneous measurements of shear stress and small-angle X-ray scattering (Rheo-SAXS) for a nonionic surfactant (C₁₄E₅)/water system, which exhibits the lamellar phase in a wide temperature range from 15–75 °C. The onion state exists in a closed region in the temperature–concentration diagram at a constant shear rate. Temperature dependence of the lamellar repeat distance (<i>d</i>) at rest has also been measured at several concentrations. It is shown that the increase of <i>d</i> with increasing temperature is necessary for the existence of the lower transition. We have investigated the change in the lamellar orientation in the lamellar-to-onion and onion-to-lamellar transition processes near the upper and lower transition temperatures. For all four kinds of transition processes, the following change in the lamellar orientation is observed; lamellar state (oriented to the velocity gradient direction) ↔ further enhancement of the orientation to the velocity gradient direction ↔ enhancement of the orientation to the neutral direction ↔ onion state

Additional file 1: Table S1. of Effects of preoperative cinacalcet hydrochloride treatment on the operative course of parathyroidectomy and pathological changes in resected parathyroid glands

Characteristics of patients with or without adhesion lesions in resected PTGs. (PPTX 54 kb

Additional file 3: of Optimising first- and second-line treatment strategies for untreated major depressive disorder — the SUN☺D study: a pragmatic, multi-centre, assessor-blinded randomised controlled trial

SUN☺D Investigators and committee members. (DOCX 17 kb

Additional file 2: of Optimising first- and second-line treatment strategies for untreated major depressive disorder — the SUN☺D study: a pragmatic, multi-centre, assessor-blinded randomised controlled trial

Figure S1. Schedule of the assessments. Table S1. Incidence of suicidality, manic switches or any serious adverse events up to week 9 for step 1 randomisation. Table S2. Incidence of suicidality, manic switches or any serious adverse events up to week 25 for step 1 randomisation. Table S3. Two pre-specified subgroup analyses for step 1 randomisation. Table S4. Four pre-specified sensitivity analyses for step 1 randomisation. Table S5. Incidence of suicidality, manic switches or any serious adverse events up to week 9 for step 2 randomisation. Table S6. Incidence of suicidality, manic switches or any serious adverse events up to week 25 for step 2 randomisation. Table S7. Three pre-specified subgroup analyses for step 2 randomisation. (DOCX 32 kb

Additional file 1: of Optimising first- and second-line treatment strategies for untreated major depressive disorder — the SUN☺D study: a pragmatic, multi-centre, assessor-blinded randomised controlled trial

Blinded data analyses statement of interpretation. (PDF 336 kb