Energy dissipation via the internal fracture of the silica particle network in inorganic/organic double network ion gels.

Inorganic/organic double network (DN) ion gels, which are composed of an inorganic silica particle network, an organic poly(N,N-dimethylacrylamide) (PDMAAm) network, and a large amount of ionic liquid, showed excellent mechanical strength of over 25 MPa compression fracture stress at an 80 wt% ionic liquid content. The excellent mechanical strength of these inorganic/organic DN ion gels was attributed to the energy dissipation of the inorganic/organic DN structure. It has been considered that the energy dissipation in inorganic/organic DN ion gels is caused by the internal fracture of the silica particle network, which is preferentially fractured by deformation. However, no studies aiming to investigate the internal fracture of the silica particle network in inorganic/organic DN ion gels have been conducted by direct approaches. In this study, the internal fracture of the silica particle network in the inorganic/organic DN ion gel was directly evaluated by a small angle X-ray scattering (SAXS) technique. The synchrotron SAXS measurements conducted under a uniaxial loading-unloading process demonstrated that the aggregation size of the silica particle network irreversibly decreased with uniaxial stretch. Based on these results, it was clarified that the energy dissipation of the inorganic/organic DN ion gels was attributed to the internal fracture of the silica particle network.

Inorganic/organic nanocomposite ion gels with well dispersed secondary silica nanoparticles.

We have previously reported tough inorganic/organic nanocomposite (NC) ion gels composed of silica particles and poly(N,N-dimethylacrylamide) (PDMAAm) networks and a large amount of ionic liquid. In this study, the network structure and toughening mechanism of NC ion gels were investigated. The NC ion gels showed characteristic mechanical properties; i.e. the stress was significantly increased at a highly elongated state. In addition, the NC ion gels showed an almost elastic mechanical property, which was completely different from that of our other developed inorganic/organic tough ion gels named double-network (DN) ion gels. It was found from structural observation that secondary silica nanoparticles dispersed well in the NC ion gel. It was also found that some of the secondary silica nanoparticles had a ring-like structure which would incorporate PDMAAm chains. From the silica particle content dependency on stress-strain curves of inorganic/organic NC ion gels, it was inferred that the secondary silica particles could serve as a movable cross-linker of PDMAAm chains in the NC ion gel.

Development of an HKUST-1 Nanofiller-Templated Poly(ether sulfone) Mixed Matrix Membrane for a Highly Efficient Ultrafiltration Process.

Mixed-matrix membranes (MMMs) have been drawing increasing attention due to the high permeability and high rejection capabilities for highly efficient wastewater treatment applications. Nonetheless, improving the water permeance while maintaining the high rejection capability is still an ongoing challenge for the practically state-of-the-art MMMs. Herein, a new class of poly(ether sulfone) (PES) based MMM containing metal-organic framework (MOF) nanofillers of HKUST-1 and blending with poly(methyl methacrylate- co-methacrylic acid) (PMMA- co-MAA) copolymer, designated as HKUST-1@mPES MMM, were developed for the highly efficient ultrafiltration (UF) process. In this study, the nanosized HKUST-1 nanofillers were removed by water dissolution as sacrificial templating materials, so that the additional nanovoids were deliberately generated throughout the dense polymer matrix. The introduction of PMMA- co-MAA copolymer facilitated the even dispersion of HKUST-1 nanofillers in a polymer matrix, by constructing the bridge connection between inorganic nanofillers and organic matrix. The resultant HKUST-1@mPES MMM exhibited a high pure water permeability (PWP) up to 490 L·m-2·h-1·bar-1, substantially reaching nearly 3 times higher than that of the mPES membrane without HKUST-1 nanofillers loading and maintaining a relatively high BSA rejection rate of 96% without obvious deterioration. The newly developed HKUST-1@mPES MMM thereby exhibited a comparable separation efficiency compared to the cutting-edge UF membranes reported so far. Overall, the nanovoid-generated approach provides new insight into developing advanced MMMs used for highly efficient water treatment applications.

Tough and stretchable inorganic/organic double network ion gel containing gemini-type ionic liquid as a multiple hydrogen bond cross-linker.

Tough and stretchable inorganic/organic double network ion gels containing gemini-type ionic liquids with two OH groups in the di-cation, which can work as multiple hydrogen bond-based weak cross-linkers of the gel networks, are developed.

Inorganic/Organic Double-Network Ion Gels with Partially Developed Silica-Particle Network.

Tough inorganic/organic composite network gels consisting of a partially developed silica-particle network and a large amount of an ionic liquid, named micro-double-network (µ-DN) ion gel, are fabricated via two methods. One is a one-pot/one-step process conducted using a simultaneous network formation via sol-gel reaction of tetraethyl orthosilicate and free radical polymerization of N, N-dimethylacrylamide in an ionic liquid. When the network formation rates of the inorganic and organic networks are almost the same, the µ-DN structure is formed. The second method is simpler and involved the use of silica nanoparticles as the starting material. By controlling the dispersion state of the silica nanoparticles in an ionic liquid, the µ-DN structure is formed. In both µ-DN ion gels, silica nanoparticles partially aggregate and form network-like clusters. When a large deformation is induced in the µ-DN ion gels, the silica-particle clusters rupture and dissipate the loaded energy. The fracture stress and Young's modulus of the µ-DN ion gel increase as the size of the silica nanoparticles decreases. The increment in the mechanical strength would have been caused by the increase in the total van der Waals attraction forces and the total number of hydrogen bonding in the silica-particle networks.

Preperimetric Glaucoma Prospective Study (PPGPS): Predicting Visual Field Progression With Basal Optic Nerve Head Blood Flow in Normotensive PPG Eyes.

PURPOSE: To investigate the site specificity of visual field changes in eyes with normotensive preperimetric glaucoma (PPG), and to determine factors influencing visual field progression. METHODS: This prospective study comprised 84 eyes of 84 normotensive PPG patients followed for at least 16 months. Optic nerve head (ONH) blood flow was assessed with tissue-area mean blur rate (MBRT), derived from laser speckle flowgraphy. Total deviation (TD) was measured in each sector of the Garway-Heath map to evaluate the site specificity of visual field loss. Subjects with a TD slope in the first quartile were classified as progressive, and other subjects as nonprogressive. Linear and multiple regression analyses were performed to determine factors affecting visual field progression. RESULTS: TD in the superior sector significantly decreased in the subjects overall during the follow-up periods (-0.48 ± 1.92 dB/y, P = 0.025). Linear regression analysis showed that basal MBRT-inferior was correlated significantly with TD-superior slope (r = 0.332, P = 0.002). Furthermore, basal MBRT was significantly lower in this sector in the progressive than the nonprogressive group (P = 0.010). Multiple linear regression analysis revealed that basal MBRT-inferior was the only predictive factor for TD-superior slope (ß = 0.329, P = 0.005). CONCLUSIONS: These findings suggest that superior-sector visual field progression is most common in normotensive PPG eyes, and that reduced basal ONH blood flow is associated with visual field progression. TRANSLATIONAL RELEVANCE: These findings provide new insight into the involvement of ONH blood flow impairment in glaucoma pathogenesis, and demonstrate the importance of assessing ONH blood flow to determine visual field progression in normotensive PPG.

Preperimetric Glaucoma Prospective Observational Study (PPGPS): Design, baseline characteristics, and therapeutic effect of tafluprost in preperimetric glaucoma eye.

PURPOSE: There is no consensus on the diagnosis or treatment policy for Preperimetric Glaucoma (PPG) because the pathogenesis of PPG is not clear at this time. Preperimetric Glaucoma Prospective Observational Study (PPGPS) is a first multicenter, prospective, observational study to clarify the pathogenesis of PPG. This article indicates study design, patient baseline characteristics, and analysis focused on optic nerve head (ONH) blood flow in PPG, as well as the intraocular pressure (IOP) -lowering effect and ONH blood flow-improving effects of Tafluprost. METHOD: In this study, 122 eyes from 122 subjects (mean age: 53.1 ± 14.3) newly diagnosed as PPG were enrolled. The circumpapillary retinal nerve fiber layer thickness (cpRNFLT) was evaluated with optical coherence tomography (OCT). The ONH blood flow was measured with laser speckle flowgraphy. The therapeutic effect of Tafluprost was evaluated at Month 0 (ONH blood flow-improving effect) and Month 4 (IOP-lowering effect). RESULTS: The untreated IOP, cpRNFLT, and baseline Mean deviation (MD) value was 16.4 ± 2.5 mmHg, 80.4 ± 8.2 µm, and -0.48 ± 1.29 dB, respectively. In the site-specific visual field evaluation using the sector map, there was no appreciable site-specific visual field defect in the eye with PPG. The inferior region of cpRNFLT in 4-quadrant OCT sector analysis and 6 o'clock region in 12-o'clock OCT sector analysis was the highest rate of abnormality in PPG eyes. Topical administration of Tafluprost significantly reduced IOP from 16.4 ± 2.5 mmHg at baseline to 14.5 ± 2.3 mmHg at Month 4 (P < 0.001, paired t-test). In the linear regression analysis, there was a significant relationship between the increase of ONH blood flow and baseline value. CONCLUSION: PPGPS is a first prospective study focusing on the pathology of PPG. This study is expected to elucidate the pathology of PPG, with evidence useful for determining a treatment strategy for PPG.

Inorganic/Organic Double-Network Gels Containing Ionic Liquids.

Highly robust ion gels, termed double-network (DN) ion gels, composed of inorganic/organic interpenetrating networks and a large amount of ionic liquids (ILs), are fabricated. The DN ion gels with an 80 wt% IL content show extraordinarily high mechanical strength: more than 28 MPa of compressive fracture stress. In the DN ion gel preparation, a brittle inorganic network of physically bonded silica nanoparticles and a ductile organic network of polydimethylacrylamide (PDMAAm) are formed in the IL. Because of the different reaction mechanisms of the inorganic/organic networks, the DN ion gels can be formed by an easy and free-shapeable one-pot synthesis. They can be prepared in a controllable manner by manipulating the formation order of the inorganic and organic networks via not only multistep but also single-step processes. When silica particles form a network prior to the PDMAAm network formation, DN ion gels can be prepared. The brittle silica particle network in the DN ion gel, serving as sacrificial bonds, easily ruptures under loading to dissipate energy, while the ductile PDMAAm network maintains the shape of the material by the rubber elasticity. Given the reversible physical bonding between the silica particles, the DN ion gels exhibit a significant degree of self-recovery by annealing.

Optic Nerve Head Blood Flow, as Measured by Laser Speckle Flowgraphy, Is Significantly Reduced in Preperimetric Glaucoma.

PURPOSE: To compare optic nerve head (ONH) blood flow in healthy eyes, eyes with preperimetric glaucoma (PPG), and eyes with mild normal-tension glaucoma (NTG) using laser speckle flowgraphy (LSFG). METHODS: In 172 eyes (normal: 44 eyes; PPG: 62 eyes; mild NTG: 66 eyes), LSFG was used to measure mean blur rate in the ONH tissue area (MBRT), an index of capillary blood flow. Multiple regression analysis was performed to determine factors affecting circumpapillary retinal nerve fiber layer thickness (cpRNFLT), mean deviation (MD) and pattern standard deviation (PSD) of the visual field. RESULTS: Despite similar characteristics in age, refractive error and systemic variables among the study groups, MBRT in the normal eyes differed significantly from both the PPG and mild NTG eyes (P = 0.001, P < 0.001, respectively). Multiple regression analysis revealed that MBRT was an independent factor affecting cpRNFLT, MD and PSD (P < 0.001, P = 0.001, P = 0.003, respectively). CONCLUSION: ONH blood flow was detectibly reduced in eyes with PPG, in close association with structural and visual field damage. This suggests that measuring ONH tissue-area blood flow with LSFG may be a useful way of monitoring glaucoma severity, even in the early stages of glaucoma.

Host manipulation by an ichneumonid spider ectoparasitoid that takes advantage of preprogrammed web-building behaviour for its cocoon protection.

Host manipulation by parasites and parasitoids is a fascinating phenomenon within evolutionary ecology, representing an example of extended phenotypes. To elucidate the mechanism of host manipulation, revealing the origin and function of the invoked actions is essential. Our study focused on the ichneumonid spider ectoparasitoid Reclinervellus nielseni, which turns its host spider (Cyclosa argenteoalba) into a drugged navvy, to modify the web structure into a more persistent cocoon web so that the wasp can pupate safely on this web after the spider's death. We focused on whether the cocoon web originated from the resting web that an unparasitized spider builds before moulting, by comparing web structures, building behaviour and silk spectral/tensile properties. We found that both resting and cocoon webs have reduced numbers of radii decorated by numerous fibrous threads and specific decorating behaviour was identical, suggesting that the cocoon web in this system has roots in the innate resting web and ecdysteroid-related components may be responsible for the manipulation. We also show that these decorations reflect UV light, possibly to prevent damage by flying web-destroyers such as birds or large insects. Furthermore, the tensile test revealed that the spider is induced to repeat certain behavioural steps in addition to resting web construction so that many more threads are laid down for web reinforcement.

Comparison of the reactivity of carbohydrate photoaffinity probes with different photoreactive groups.

A judicious choice of photoreactive group is critical in successful photoaffinity labeling studies of small molecule-protein interactions. A set of carbohydrate-based photoaffinity probes was prepared to compare the effects of three major photoreactive groups on the efficiency and selectivity of crosslinking a binding protein with low affinity. We showed that, despite the low crosslinking yield, the diazirine probe displayed the high ligand-dependent reactivity consistent with the ideal mechanism of photoaffinity labeling. Moreover, we demonstrated that, among the three photoreactive groups, only the diazirine probe achieved highly selective crosslinking of a low-affinity binding protein in cell lysate.

Progression of visual field defects in eyes with different optic disc appearances in patients with normal tension glaucoma.

PURPOSE: To investigate the relationship between the optic disc appearance and the progression of visual field defects in eyes with normal tension glaucoma (NTG). METHODS: Two hundred nine patients with NTG, who were being treated with topical antiglaucoma drugs and had been followed for at least 3 years, were studied. The baseline optic disc appearance was classified into 4 types: focal ischemic (FI), myopic glaucomatous (MY), senile sclerotic (SS), and generalized cup enlargement (GE). The progression of the NTG was assessed by the slope of the mean deviations (MDs) obtained from the visual field results collected during the follow-up examinations. The baseline and mean intraocular pressures (IOPs) were also followed. RESULTS: Twenty-seven patients were placed in the FI group, 63 into the MY group, 24 into the SS group, and 43 into the GE group. Fifty-two patients (24.9%) could not be classified. There were no significant differences in the percentage reduction of the IOP among the 4 groups. The MD slope in the GE group (-0.51±0.74 dB/y) was significantly steeper than that in the other groups. Regression analyses showed that the factors most associated with the MD slope were the age in the FI (r, -0.495) and the GE (r=0.496) groups, and the relative reduction of the IOP (r=0.413) in the SS group. None of the factors in the MY group was significantly associated with the MD slope. CONCLUSIONS: The rate of progression of the field defects, the MD slope, in patients with NTG is possibly dependent on the baseline optic disc appearance. Thus, the optic disc appearance may be useful for the management of patients with NTG.

Presence of myocilin sequence variants in Japanese patients with open-angle glaucoma.

PURPOSE: To examine the myocilin (MYOC) gene for mutations in Japanese patients with primary open-angle glaucoma (POAG) and to determine the phenotypes of the patients with the mutations. METHODS: One-hundred thirty-eight unrelated Japanese patients with POAG were studied. Genomic DNA was extracted from leukocytes of peripheral blood, and the three coding exons including the intron-exon boundaries were amplified by polymerase chain reaction (PCR) and directly sequenced bi-directionally. RESULTS: Two sequence variants were identified, one novel non-synonymous amino acid change (p.Gln297His) and one reported synonymous amino acid change (p.Ala363Thr). These mutations were not detected in the 118 ethnically-matched controls. p.Gln297His was found in a 70-year-old man, who developed POAG at a late age, and his intraocular pressure was high. p.Ala363Thr was found in two cases, and both patients developed POAG at an early age and had high intraocular pressures that responded poorly to medical treatment. CONCLUSIONS: Two non-synonymous variants, p.Gln297His and p.Ala363Thr, indicate that they are involved in the pathogenesis of POAG. p.Ala363Thr has been found in another Japanese population and would be useful in genetic testing.