Search

The effective interaction between macroanions immersed in an electrolyte solution was calculated using an integral equation theory of liquids to study the solvent granularity effect on the effective attraction mediated by cations. Explicit and implicit solvent models were examined. The effective attraction for the explicit solvent model was found to be stronger than that for the implicit solvent model. This solvent effect was remarkably enhanced only when the effective attraction between macroanions was strong; this means that the solvent effect is not a usual excluded volume effect. The intensification mechanism of the attraction by the solvent granularity is analyzed in the present study, and an indirect mechanism is proposed. [ABSTRACT FROM AUTHOR]

• The presentable color range of a projector is limited. • We developed a projection method to perceptually broaden the range. • We employ one of the visual illusion, color constancy. • Our method broadens the range compared to physically-based method. • Our method can present colors that cannot be presented physically. With projection mapping, we can control the appearance of real-world objects by adding illumination. A projector can be used to control light reflected from an object, where the reflected light depends not only on the projection but also on the reflectance and environmental light. Because the resulting colors are affected by the reflectance and environmental light, the presentable color range of a projector is limited. The purpose of this work is to broaden this limited range by focusing on the perceived colors. Although our eyes capture reflected light to perceive the colors of an object, the colors perceived by humans are not always the same as the actual colors, and there are often significant differences between them because of the human visual system. To overcome the limitations of a projector based on human perception, we intentionally generate this difference by inducing a visual illusion, namely, color constancy. In this work, we designed an algorithm to determine the projected colors for presenting the desired colors perceptually by employing a color constancy effect. In addition, we conducted a user study and confirmed that our algorithm can (1) create a misperception regarding the color of illumination, (2) broaden the presentable color range of a projector, and (3) shift the perceptual colors in the desirable direction. [ABSTRACT FROM AUTHOR]

The infrared vibrational echo measurement has the capacity to discriminate among spectral line-broadening processes according to time scale. Modelling infrared vibrational echoes in condensed phases at the molecular level requires computing the dynamics of large, anharmonic systems, a task far more tractable in classical than in quantum mechanics. The use of classical trajectory data to compute vibrational echoes raises the issue of the quantitative relationship between classical and quantum vibrational echo calculations. This relationship is addressed here in classical and quantum calculations of the vibrational echo for an anharmonic oscillator coupled to a harmonic solvent. Our calculations demonstrate that for a high-frequency solute coupled to a low-frequency solvent, in which the echo is dominated by pure dephasing dynamics, a fully classical calculation can represent a reasonable approximation to the quantum mechanical result. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Palladium catalyzed intermolecular 1,2-addition of arylboronate to unactivated ketone was investigated. NHC-coordinated palladacycle 4c exhibited catalytic activity for the reactions and provided the corresponding tertiary alcohols and γ,γ-disubstituted γ-lactones in good to excellent yields. [ABSTRACT FROM AUTHOR]

Examines the liquid structures of water at the electrode-solution interface. Use of the reference interaction site method; Types of surface geometry examined; Dependence of the water molecule orientation on the surface structure; Changes in the orientation of water molecules.

The 2D ordering of bacteriorhodopsins in a lipid bilayer was studied using a binary hard-disk model. The phase diagrams were calculated taking into account the lateral depletion effects. The critical concentrations of the protein ordering for monomers and trimers were obtained from the phase diagrams. The critical concentration ratio agreed well with the experiment when the repulsive core interaction between the depletants, namely, lipids, was taken into account. The results suggest that the depletion effect plays an important role in the association behaviors of transmembrane proteins. [ABSTRACT FROM AUTHOR]

We investigate the dependence of the diffusion coefficient of a large solute particle on the solvation structure around a solute. The diffusion coefficient of a hard-sphere system is calculated by using a perturbation theory of large-particle diffusion with radial distribution functions around the solute. To obtain the radial distribution function, some integral equation theories are examined, such as the Percus–Yevick (PY), hypernetted-chain (HNC), and modified HNC theories using a bridge function proposed by Kinoshita (MHNC) closures. In one-component solvent systems, the diffusion coefficient depends on the first-minimum value of the radial distribution function. The results of the MHNC closure are in good agreement with those of calculation using the radial distribution functions of Monte Carlo simulations since the MHNC closure very closely reproduces the radial distribution function of Monte Carlo simulations. In binary-solvent mixtures, the diffusion coefficient is affected by the larger solvent density distribution in the short-range part, particularly the height and sharpness of the first peak and the depth of the first minimum. Since the HNC closure gives the first peak that is higher and sharper than that of the MHNC closure, the calculated diffusion coefficient is smaller than the MHNC closure result. In contrast, the results of the PY closure are qualitatively and quantitatively different from those of the MHNC and HNC closures. [ABSTRACT FROM AUTHOR]

To discuss the effective interactions between macroanions, such as acidic proteins, the radial distribution function between macroanions, g MM ( r ), was calculated using an integral equation theory with a charged hard spheres model under weak coupling conditions. Explicit and implicit solvent models were examined. The g MM ( r ) for the explicit solvent model indicated a significant peak at the contact distance, which was caused by the translational motion of solvent molecules. In contrast, the g MM ( r ) for the implicit solvent model did not indicate any significant peak at the distance because of no explicit solvent particles. Although there was a significant difference in the g MM ( r ) for the explicit and implicit models, the structure factor S MM ( k ) was nearly the same and the shapes and peak shifts caused by macroanion concentration changes were also similar to the experimental results. To reproduce the first sharp peak in g MM ( r ), the structure factor S MM ( k ) provided by scattering experiments was not sufficiently long for standard analyses. This showed that the results provided by conventional small-angle scattering experiments cannot deny the existence of a first sharp peak in g MM ( r ). [ABSTRACT FROM AUTHOR]

In the Kirkwood–Buff theory, the center of each solvent molecule can be arbitrarily chosen. However, this arbitrariness is not obvious in the calculation of the Kirkwood–Buff integral for a single ion. Actually, the Kirkwood–Buff integral depends on the choice of the center of a solvent molecule, if each solvent molecule has a dipole moment and the solute has a net charge. A few examples based on molecular dynamics simulations are shown. A surrogate definition for the center of a water molecule is also shown. A good agreement between the calculated and experimental values of partial molar volumes for single ions is observed. [ABSTRACT FROM AUTHOR]

Attractive interaction between macroanions mediated by divalent cations is studied using an Ornstein–Zernike equation with hypernetted-chain closure. The calculated results indicate that the divalent cations mediate the strong attraction and that this attractive force is much stronger than that mediated by monovalent cations. In this article, we shed light on effects of the co-existing of monovalent cations because the attractive interaction mediated by multivalent cations is observed in various biological fluids that also contain monovalent cations. When the system also contains monovalent cations, they suppress the attraction mediated by the divalent cations. However, the attraction remains and the reentrant behavior of attraction appears due to the exchange of attraction-mediating divalent cations for monovalent cations if the charge of the macroanions is sufficiently large. [ABSTRACT FROM AUTHOR]

Abstract: The effect of a solvent on the activity coefficient of a macromolecule in crowding media was investigated using the hard-sphere model. The crowding media comprised solvent molecules and crowding agents, and the activity coefficient of a macromolecule immersed in the media was calculated using the integral equation theory. The dependence of the activity coefficient on the concentration of crowding agent for the explicit-solvent model was completely different from that for the inert-solvent model, which has been adopted in conventional studies of crowding problems. Those results indicate that solvent granularity can play an important role in the description of the activity coefficient of macromolecules. [Copyright &y& Elsevier]

The article examines microencapsulated and related catalysts for organic chemistry and organic synthesis. It focuses on polystyrene-based catalysts, polymer incarcerated catalysts and polyurea-encapsulated catalyst. Other processes and compounds used in the research include microencapsulated scandium trifluoromethanesulfonate, polymer incarcerated palladium and polyurea-encapsulated osmium tetroxide.

Abstract: Highly active immobilized ruthenium catalysts, which can be used for oxidation of alcohols and sulfides, were developed on the basis of the polymer-micelle incarcerated (PMI) method. The catalysts could be recovered and reused several times without loss of activity and no metal leaching was observed. Selection of micelle-forming conditions and polymer structures were key in achieving high activities. TEM and SEM analyses were conducted to observe the structures of PMI-Ru. [Copyright &y& Elsevier]

Subnanometer Pd clusters stabilized within micelles of random copolymers were formed by direct immobilization of Pd(0) via ligand exchange. The clusters were estimated to contain approximately seven Pd atoms on average (cluster diameter ≈ 0.7 nm). Several Pd-containing micelle morphologies could be obtained by polymer cross-linking. These micelles containing Pd clusters were demonstrated to be efficient catalysts for hydrogenations and Heck reactions. [ABSTRACT FROM AUTHOR]

Effective interactions between O-sized anions in various electrolyte solutions were calculated by using the integral equation theory with some simple models. The results indicated that only multivalent cations mediated a strong effective attraction between O-sized anions at a certain concentration. The effective interaction turned from repulsive to attractive as the electrolyte concentration increased, and the effective attraction decreased when more electrolyte was added. Moreover, the effective interactions between O-sized anions in the electrolyte solution did not present a long repulsive tail, although the effective attraction caused by the divalent cations appeared. By contrast, the effective attraction mediated by monovalent cations and the reentrant behavior did not appear and the effective interaction was basically repulsive. These behaviors agree with the experimental results for reentrant condensation of acidic proteins in various electrolyte solutions. The calculated results suggest that the dissociated carboxylic acidic groups on the proteins form attractive patches between proteins under certain concentration conditions. [ABSTRACT FROM AUTHOR]

We report a 74-year-old male patient who presented with left hemiplegia and disturbance of consciousness. Computed tomography revealed diffuse subarachnoid hemorrhage, which was prominent in the right Sylvian and basal cisterns. Digital subtraction angiography revealed absence of the C2 segment of the right internal carotid artery (ICA) and a significantly developed circuminfundibular anastomosis. Occlusion of the bilateral vertebral arteries (VAs) was also seen. The upper basilar artery was supplied by the circuminfundibular anastomosis and collaterals from the VAs. Since the source of bleeding was unclear, the patient was treated conservatively. Circuminfundibular anastomosis is a potential anastomosis around the pituitary stalk. It is formed by the superior hypophyseal arteries, prechiasmal arteries, and infundibular arteries bilaterally. Agenesis of the contralateral ICA often leads to development of ICA-ICA anastomoses. In this case, the anastomosis developed due to agenesis of the C2 segment of the right ICA and occlusion of the bilateral VAs. [ABSTRACT FROM AUTHOR]

A new type of immobilized palladium, PI (polymer incarcerated) Pd (2b), from Pd(PPh3)4 and copolymer (1b) has been developed. The excellent activity of PI Pd has been demonstrated in hydrogenation of various olefins, benzyl ethers, and nitro and aromatic compounds. PI Pd is tolerant under high pressure and high temperature and can be recovered and reused several times without loss of activity even under harsh conditions. Moreover, PI Pd is highly resistant to poisoning by sulfur. [ABSTRACT FROM AUTHOR]

The changes in excess thermodynamic quantities upon the contact of two solutes immersed in a solvent are analyzed using the radial-symmetric and three-dimensional versions of the integral equation theory. A simple model mimicking a solute in water is employed. The solute-solute interaction energy is not included in the calculations. Under the isochoric condition, the solute contact always leads to a positive entropy change irrespective of the solute solvophobicity or solvophilicity. The energy change is negative for solvophobic solutes while it is positive for solvophilic ones. Under the isobaric condition, the contact of solvophobic solutes results in system-volume compression but that of solvophilic ones gives rise to expansion. Effects of the compression and expansion on the changes in enthalpy and entropy are enlarged with rising temperature. When the solute solvophobicity is sufficiently high, the entropy change (multiplied by the absolute temperature) can become negative due to the compression, except at low temperatures with the result of an even larger, negative enthalpy change. The expansion in the case of solvophilic solutes leads to a large, positive entropy change accompanied by an even larger, positive enthalpy change. The changes in enthalpy and entropy are strongly dependent on the temperature. However, the changes in enthalpy and entropy are largely cancelled out and the temperature dependency of the free-energy change is much weaker. The authors also discuss possible relevance to the enthalpy-entropy compensation experimentally known for a variety of physicochemical processes in aqueous solution such as protein folding. [ABSTRACT FROM AUTHOR]

Background: Sarcopenia has been identified as a potential negative prognostic factor in cancer patients. In this study, our objective was to investigate the relationship between the assessment method for sarcopenia using the masseter muscle volume measured on computed tomography (CT) images and the life expectancy of patients with oral cancer. We also developed a learning model using deep learning to automatically extract the masseter muscle volume and investigated its association with the life expectancy of oral cancer patients. Methods: To develop the learning model for masseter muscle volume, we used manually extracted data from CT images of 277 patients. We established the association between manually extracted masseter muscle volume and the life expectancy of oral cancer patients. Additionally, we compared the correlation between the groups of manual and automatic extraction in the masseter muscle volume learning model. Results: Our findings revealed a significant association between manually extracted masseter muscle volume on CT images and the life expectancy of patients with oral cancer. Notably, the manual and automatic extraction groups in the masseter muscle volume learning model showed a high correlation. Furthermore, the masseter muscle volume automatically extracted using the developed learning model exhibited a strong association with life expectancy. Conclusions: The sarcopenia assessment method is useful for predicting the life expectancy of patients with oral cancer. In the future, it is crucial to validate and analyze various factors within the oral surgery field, extending beyond cancer patients. [ABSTRACT FROM AUTHOR]

The diagnosis of oral mucosal diseases is a significant challenge due to their diverse differential characteristics. Risk assessment of lesions by visual examination is a complex process due to the lack of definitive guidelines. This study aimed to improve this process by creating a diagnostic algorithm using gaze data acquired during oral mucosal disease examinations. A total of 78 dentists were included in this study. Tobii Pro Nano® (Tobii Technology) was used to acquire gaze data during clinical photographic visual examinations. Advanced analysis tools such as support vector machines and heatmaps were used to visualize the gazing tendencies of a group of skilled oral surgeons, focusing on the number of gazes per region and the gazing time ratios. The preliminary findings showed the possibility of visualizing gazing tendencies and identifying areas of importance for diagnosis. The classification of intraoral photographs based on gross features revealed the existence of an optimal examination method for each category and diagnostically significant areas. This novel approach to analyzing gaze data has the potential to refine diagnostic techniques and increase both accuracy and efficiency. [ABSTRACT FROM AUTHOR]

The article examines several reaction conditions for the preparation of polymer-supported scandium triflate based on the polymer incarcerated (PI) method. It was found that choice of solvents at the stage of microencapsulation was key to the preparation. Polymer-supported scandium triflate may locate in hydrophilic parts of random copolymer. It is noted that the PI method can also be successfully used for the preparation of immobilized polymer-supported scandium triflate. Interesting information was obtained by transmission analysis of the polymer solutions.

Using binary hard disk mixture models, we studied the two-dimensional ordering of bacteriorhodopsins in a lipid bilayer. The phase diagrams were calculated using the thermodynamic perturbation theory. We examined two types of effective interactions to discuss the lateral depletion effects caused by repulsive core interaction between lipid molecules. The results indicate that the core repulsions drastically broaden the coexistence region for the fluid-ordered phase. • Phase separation of asymmetric binary hard-disk fluid. • The two-dimensional ordering of bacteriorhodopsin was discussed. • Phase diagrams were calculated using a thermodynamic perturbation theory. • Lateral depletion interaction induced by lipids was strong. [ABSTRACT FROM AUTHOR]

Describes the use of polymer incarcerated method to immobilize palladium catalysts onto polymers. Microencapsulation of the catalysts; Hydrogenation of benzalacetone; Recovery of the catalysts by filtration.

Solute–solvent reduced density profiles of hard-sphere fluids were calculated by using several integral equation theories for liquids. The traditional closures, Percus–Yevick (PY) and the hypernetted-chain (HNC) closures, as well as the theories with bridge functions, Verlet, Duh–Henderson, and Kinoshita (named MHNC), were used for the calculation. In this paper, a one-solute hard-sphere was immersed in a one-component hard-sphere solvent and various size ratios were examined. The profiles between the solute and solvent particles were compared with those calculated by Monte Carlo simulations. The profiles given by the integral equations with the bridge functions were much more accurate than those calculated by conventional integral equation theories, such as the Ornstein–Zernike (OZ) equation with the PY closure. The accuracy of the MHNC–OZ theory was maintained even when the particle size ratio of solute to solvent was 50. For example, the contact values were 5.7 (Monte Carlo), 5.6 (MHNC), 7.8 (HNC), and 4.5 (PY), and the first minimum values were 0.48 (Monte Carlo), 0.46 (MHNC), 0.54 (HNC), and 0.40 (PY) when the packing fraction of the hard-sphere solvent was 0.38 and the size ratio was 50. The asymptotic decay and the oscillation period for MHNC–OZ were also very accurate, although those given by the HNC–OZ theory were somewhat faster than those obtained by Monte Carlo simulations. [ABSTRACT FROM AUTHOR]

We have studied the diffusion of a large hard-sphere solute immersed in binary hard-sphere mixtures. We reveal how the boundary condition at the solute surface is affected by the solvent density around the solute. Solving equations for a binary compressible mixture by perturbation expansions, we obtain the boundary condition depending on the size ratio of binary solvent spheres. When the size ratio is 1:2, the boundary condition lies close to the slip boundary condition. By contrast, when the size ratio becomes large, the boundary condition approaches the stick boundary condition with the addition of larger solvent spheres. We find that the transition to the stick boundary condition is caused by the increase in the solvent density around the solute due to an entropic effect. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of ladder-type aromatic block copolymers containing sulfonated triphenylphosphine oxide moieties ( LadP-SPE ) are reported. Through aromatic nucleophilic substitution polycondensation and Pd-catalyzed intrapolymer Heck reaction, the target copolymers LadP-SPE with high molecular weight ( M n = 47–50 kDa, M w = 289–579 kDa) and different ion exchange capacity (IEC) values (1.04, 1.84 and 2.22 meq g −1 , by titration) were prepared. By solution casting method, all the copolymers gave transparent and bendable membranes. The membrane with IEC = 2.22 meq g −1 exhibited high proton conductivity in wide range of relative humidity (RH) at 80 °C (ca. 1.6 mS cm −1 at 20% RH and 351.2 mS cm −1 at 95% RH). Moreover, the stiff ladder structure strengthened the molecular chain which contributed to the membrane with high IEC value and water uptake to have desirable mechanical stability up to 90% RH at 80 °C. [ABSTRACT FROM AUTHOR]

We calculated the spatial distribution function, which is the one-body reduced density distribution of solvent particles around a nonspherical solute, using the three-dimensional Ornstein–Zernike equations coupled with closures. The solvent was a hard-sphere fluid, and the contact dimer of the solvent particles was the nonspherical solute. Two traditional closures, the Percus–Yevick and hypernetted-chain approximations, and three closures with bridge functions (BFs) were examined. These spatial distribution functions were compared with the results obtained by grand canonical Monte Carlo (GCMC) simulations. Three closures with BFs, such as the modified hypernetted-chain (MHNC) closure using a bridge function proposed by Kinoshita, gave precise spatial distribution functions. These results were much more accurate than those obtained by the traditional closures. The deviations from the spatial distribution function obtained by the GCMC simulation appeared only near the concave surface of the solute dimer. However, the deviations were minor compared with those between the simulation and the predictions of the two traditional closures. By contrast, the three-body correlation functions for the closures with BFs were not more accurate than those obtained by the traditional closures. • The spatial distribution functions of hard-sphere fluid around a non-spherical solute are shown. • Comparisons between the integral equation theories and GCMC simulation are carried out. • The MHNC-OZ theory gives very precise spatial distribution functions. • The triplet correlations are also discussed. [ABSTRACT FROM AUTHOR]

1,2‐Addition reactions using organoboron compounds are one of the useful syntheses of various functionalized alcohols, but they generally require a large quantity of bases. In this study, we attempted to solve this problem by synthesizing unsymmetrical 1,3‐diarylimidazoline‐type N‐heterocyclic carbene (NHC)‐coordinated C^C* cyclometalated palladium(II) complexes with bridging hydroxide ligands (CYPOHs) in two steps and one pot from the corresponding Cl bridged dimer and using them as catalysts. 2,6‐di(pentan‐3‐yl)aniline (IPent)‐based NHC coordinated PhS‐IPent‐CYPOH acted as a highly efficient catalyst for the 1,2‐addition of (hetero)arylboronates to a large number of aldehydes and ketones, including unactivated ketones, under base‐free conditions. [ABSTRACT FROM AUTHOR]

A novel, highly active immobilized ruthenium catalyst, which can be successfully used in oxidation of alcohols to aldehydes and ketones, has been developed. In contrast to most immobilized catalysts, the Ru catalyst has activity that is higher than that of the original nonimmobilized catalyst. In a batch system, the Ru catalyst was recovered and reused several times without loss of activity. The catalyst was also applied to a flow system, in which excellent conversions and yields were demonstrated. No leaching of Ru was observed in both cases. [ABSTRACT FROM AUTHOR]

Spectrally resolved infrared stimulated vibrational echo data were obtained for sperm whale carbonmonoxymyoglobin (MbCO) at 300 K. The measured dephasing dynamics of the CO ligand are in agreement with dephasing dynamics calculated with molecular dynamics (MD) simulations for MbCO with the residue histidine-64 (His64) having its imidazole E nitrogen protonated (N[subE]-H). The two conformational substate structures B[subE] and RE observed in the MD simulations are assigned to the spectroscopic A[sub1] and A[sub3] conformational substates of MbCO, respectively, based on the agreement between the experimentally measured and calculated dephasing dynamics for these substates. In the A[sub1] substate, the N[subE]-H proton and N[subΔ] of His64 are approximately equidistant from the CO ligand, while in the A[sub3] substate, the N[subE]-H of His64 is oriented toward the CO, and the N[subDelta;] is on the surface of the protein. The MD simulations show that dynamics of His64 represent the major source of vibrational dephasing of the CO ligand in the A[sub3] state on both femtosecond and picosecond time scales. Dephasing in the A[sub1] state is controlled by His64 on femtosecond time scales, and by the rest of the protein and the water solvent on longer time scales. [ABSTRACT FROM AUTHOR]

Flocking is a fascinating coordinated behavior of living organisms or self-propelled particles (SPPs). Particularly, monopolar flocking has been attractive due to its potential applications in various fields. However, the underlying mechanism behind flocking and emergence of monopolar motion in flocking of SPPs has remained obscured. Here, we demonstrate monopolar flocking of kinesin-driven microtubules, a self-propelled biomolecular motor system. Microtubules with an intrinsic structural chirality preferentially move towards counter-clockwise direction. At high density, the CCW motion of microtubules facilitates monopolar flocking and formation of a spiral pattern. The monopolar flocking of microtubules is accounted for by a torque generated when the motion of microtubules was obstructed due to collisions. Our results shed light on flocking and emergence of monopolar motion in flocking of chiral active matters. This work will help regulate the polarity in collective motion of SPPs which in turn will widen their applications in nanotechnology, materials science and engineering. • Chirality of kinesin-driven microtubules (MTs) plays a critical role in their self-organization. • Gliding MTs with chiral lattice structure self-organize into monopolar flocks and rotate in the counter-clockwise direction. • Formation of the monopolar flocks is mediated by a torque generated upon collisions between the gliding chiral MTs. [ABSTRACT FROM AUTHOR]

Background: We experienced two cases of ischemic stroke resulting from carotid artery occlusion associated with acute type A aortic dissection (ATAAD), in which carotid artery stenting before the surgery for ATAAD resulted in good clinical outcomes. Case 1 description: A 63-year-old woman was hospitalized for conscious disturbance, right hemiparesis, and total aphasia. Computed tomography of the head showed no abnormal findings. Computed tomography angiography showed ATAAD and bilateral common carotid artery occlusion. Surgery was not indicated for ATAAD because of a poor prognosis of ischemic stroke. However, carotid artery stenting of the left common carotid artery occlusion was successfully performed, and her neurological findings improved. The patient underwent hemiarch replacement for ATAAD on the day after carotid artery stenting. Her final modified Rankin Scale was 1. Case 2 Description: A 57-year-old woman was hospitalized for mild left hemiparesis. Magnetic resonance imaging showed right watershed infarction and right common carotid artery occlusion. Computed tomography angiography showed ATAAD. After hospitalization, conscious disturbance appeared and left hemiparesis worsened. Ischemic stroke indicated a poor prognosis for revascularization by surgery for ATAAD. Thus, carotid artery stenting of the right common carotid artery occlusion was performed. The patient's neurological findings improved and she underwent hemiarch replacement for ATAAD at 19 days after carotid artery stenting. Her final modified Rankin Scale was 1. Conclusions: In the present cases, although ischemic stroke was serious and precluded surgical indication for ATAAD, carotid artery stenting before surgery for ATAAD resulted in good clinical outcomes. Performing carotid artery stenting before surgery for ATAAD is challenging but achievable, and is a valid treatment option depending on the individual cases. [ABSTRACT FROM AUTHOR]

We have calculated the dielectric relaxation of water around an ion using molecular dynamics simulations. The collective motion of water near the ion showed fast relaxation, whereas the reorientational motion of individual water molecules does not have the fast component. The ratio of the relaxation time for the fast component and the bulk water was consistent with the experimental results, known as hyper-mobile water, for alkali halide aqueous solution. [ABSTRACT FROM AUTHOR]

The greatest advantage of local anesthesia (LA) in endovascular treatment (EVT) of unruptured intracranial aneurysms (UIAs) is that direct neurologic evaluation can be performed during the procedure, unlike with general anesthesia. However, the usefulness of such direct evaluation has not been established. In this study, we attempted to assess the effects of direct neurologic evaluation by identifying the causes, management, and outcomes of clinical symptoms during the procedure and procedure-related events during EVT under LA. We retrospectively evaluated the medical and radiologic data of 1000 patients (1015 UIAs) who had undergone coil embolization under LA from 2008 to 2016. Clinical symptoms were identified in 62 patients (6.2%) during the procedure. The symptoms improved during the procedure in 27 of these patients (44%) and after the procedure in another 28 (45%). One month after the procedure, 55 patients (89%) had good outcomes and 7 (11%) had poor outcomes. Procedure-related events occurred in 67 patients (6.7%); of these 67 events, 39 were symptomatic and 28 were asymptomatic. Thirty-five of the 39 symptomatic events (90%) [13 of 13 (100%) ruptures, 6 of 10 (60%) thrombus formations, and 16 of 16 (100%) thromboembolisms] were detected on the basis of clinical symptoms before angiographic changes were identified, and they were managed promptly. All 28 patients with asymptomatic events were managed safely without further complications before symptoms developed. We demonstrated that appropriate management of clinical symptoms and procedure-related events under LA led to favorable outcomes of EVT of UIAs. [ABSTRACT FROM AUTHOR]

Although endovascular coiling of unruptured aneurysms is widely accepted, the endovascular treatment of wide-neck bifurcation aneurysms remains one of the most challenging morphologies. Our purpose was to describe our experience with 24-month follow-up for the treatment of unruptured intracranial bifurcation aneurysms using the PulseRider (Cerenovus, New Brunswick, NJ). This study is a single-center, single-arm registry performed under institutional review board control to evaluate efficacy and safety of the PulseRider. Patients with bifurcation aneurysms were identified and enrolled prospectively. Angiography immediately after treatment and at 6 months, and magnetic resonance imaging and magnetic resonance angiography at 12- and 24-month follow-up were retrospectively analyzed. A modified Rankin score was obtained prior to procedure, at discharge, and at 6-, 12- and 24-month follow-up visits. Eight patients with a mean age of 66 years were treated with the PulseRider. All patients had bifurcation aneurysms (2 anterior communicating, 2 carotid terminus, and 4 basilar apex). The aneurysm diameters ranged from 4.6 to 13.6 mm (mean 7.4 mm) with dome/neck ratio ranging from 1.4 to 2.2 (mean 1.6). In all cases, the PulseRider was successfully deployed. Complete occlusion was demonstrated at 6-month follow-up on 6 of 8 (75%), near complete occlusion in 1 of 8 (12.5%), and residual aneurysm in 1 of 8 (12.5%) patients. There was no change or recurrence on magnetic resonance angiography, nor clinical complication after the procedure through 24-month follow-up. Our experience with 24-month follow-up demonstrated favorable efficacy in the treatment of intracranial wide-neck bifurcation aneurysms using the PulseRider. [ABSTRACT FROM AUTHOR]

Stent-assisted coil embolization (SAC) for treating anterior communicating artery (AcomA) aneurysms is safe and effective. Straightening of parent vessels by stent placement can lead to progressive thrombosis. We describe our experience with SAC for AcomA aneurysms and demonstrate the effect of straightening the parent vessels. A total of 26 patients with AcomA aneurysms were treated using SAC in our institute between July 2010 and December 2017. Follow-up digital subtraction angiography was performed 6 months after treatment, magnetic resonance angiography was performed every year, and outcomes were analyzed. From all aneurysms (n = 24), 12 (50.0%) were neck remnant, and 12 (50.0%) were dome-filling types immediately after the procedure. At the 6-month digital subtraction angiography follow-up (n = 22), 13 (59.1%) aneurysms were complete obliteration, 8 (36.4%) were neck remnant, and 1 (4.5%) was dome filling. The median parent vessel angle was measured preoperatively at 98.1°, increased to 124.8° immediately after stent deployment, and further increased to 149.6° at the 6-month follow-up. Progressive thrombosis was observed in 13 of 22 (59.1%) aneurysms. The parent vessel angle change immediately after stent deployment in the progressive thrombosis group tended to be larger than that observed in the no thrombosis group; this change was significant at the 6-month follow-up. The median follow-up term was 18 months. No patients required retreatment. Good SAC outcomes were achieved for AcomA aneurysms, and hemodynamic changes related to straightening of the parent vessels is a consideration in SAC. [ABSTRACT FROM AUTHOR]

Background Living systems are characterized by the dynamic assembly and disassembly of biomolecules. The dynamical ordering mechanism of these biomolecules has been investigated both experimentally and theoretically. The main theoretical approaches include quantum mechanical (QM) calculation, all-atom (AA) modeling, and coarse-grained (CG) modeling. The selected approach depends on the size of the target system (which differs among electrons, atoms, molecules, and molecular assemblies). These hierarchal approaches can be combined with molecular dynamics (MD) simulation and/or integral equation theories for liquids, which cover all size hierarchies. Scope of review We review the framework of quantum mechanical/molecular mechanical (QM/MM) calculations, AA MD simulations, CG modeling, and integral equation theories. Applications of these methods to the dynamical ordering of biomolecular systems are also exemplified. Major conclusions The QM/MM calculation enables the study of chemical reactions. The AA MD simulation, which omits the QM calculation, can follow longer time-scale phenomena. By reducing the number of degrees of freedom and the computational cost, CG modeling can follow much longer time-scale phenomena than AA modeling. Integral equation theories for liquids elucidate the liquid structure, for example, whether the liquid follows a radial distribution function. General significance These theoretical approaches can analyze the dynamic behaviors of biomolecular systems. They also provide useful tools for exploring the dynamic ordering systems of biomolecules, such as self-assembly. This article is part of a Special Issue entitled “Biophysical Exploration of Dynamical Ordering of Biomolecular Systems” edited by Dr. Koichi Kato. [ABSTRACT FROM AUTHOR]

Proton exchange membrane fuel cells (PEMFCs) are promising devices for clean power generation in automotive, sta tionary, and portable applications. Perfluorosulfonic acid (PFSA) ionomers (for example, Nafion) have been the benchmark PEMs; however, several problems, including high gas permeability, low thermal stability, high production cost, and environmental incompatibility, limit the widespread dissemination of PEMFCs. It is believed that fluorine-free PEMs can potentially address all of these issues; however, none of these membranes have simultaneously met the criteria for both high performance (for example, proton conductivity) and durability (for example, mechanical and chemical stability). We present a polyphenylene-based PEM (SPP-QP) that fulfills the required properties for fuel cell applications. The newly designed PEM exhibits very high proton conductivity, excellent membrane flexibility, low gas permeability, and extremely high stability, with negligible degradation even under accelerated degradation conditions, which has never been achieved with existing fluorine-free PEMs. The polyphenylene PEM also exhibits reasonably high fuel cell performance, with excellent durability under practical conditions. This new PEM extends the limits of existing fluorine-free proton-conductive materials and will help to realize the next generation of PEMFCs via cost reduction as well as the performance improvement compared to the present PFSA-based PEMFC systems. [ABSTRACT FROM AUTHOR]

Yeh and Hummer's simplified estimation method has often been adopted to obtain diffusion coefficients for solute molecules using molecular dynamic simulation. However, the simplified formula is not necessarily valid when a small basic cell is used. Therefore, we conducted molecular dynamics simulations of aqueous protein solution to estimate the diffusion coefficient for the infinite dilution limit. We confirmed a deviation from the simplified formula in the simulation data and rationalized the discrepancy based on the unsimplified formula. [Display omitted] • Macromolecular diffusion coefficients depend on the system volume. • Deviation from conventional Yeh–Hummer method and the rationalization. • An approach to estimate the diffusion coefficient for the infinite dilution limit. [ABSTRACT FROM AUTHOR]

The synthesis and properties of anionconductive aromatic copolymerscontaining oligophenylene moieties as a scaffold for quaternized ammoniumgroups are reported. Our new hydrophilic components consist of a chemicallyrobust oligophenylene main chain modified with a high density of ionicgroups. A partially fluorinated oligo(arylene ether) was employedas a hydrophobic block. The targeted copolymers (QPE-bl-9) were synthesized via nickel-mediated coupling polymerization,followed by chloromethylation, quaternization, and ion exchange reactions.QPE-bl-9 provided tough, bendable membranes by solutioncasting. The resulting membrane with the highest ion exchange capacity(IEC = 2.0 mequiv g–1) exhibited high hydroxideion conductivity (138 mS cm–1) in water at 80 °C.Reasonable alkaline stability of QPE-bl-9 membranewas confirmed in 1 M KOH aqueous solution for 1000 h at 40 °C.A noble metal-free fuel cell with QPE-bl-9 used asthe membrane and electrode binder was successfully operated. A maximumpower density of 510 mW cm–2was achieved at a currentdensity of 1.20 A cm–2with hydrazine as the fueland O2as the oxidant. [ABSTRACT FROM AUTHOR]

We have developed an efficient system for triphase reactions using a microchannel reactor. Using this system, we conducted hydrogenation reactions that proceeded smoothly to afford the desired products quantitatively within 2 minutes for a variety of substrates. The system could also be applied to deprotection reactions. We could achieve an effective interaction between hydrogen, substrates, and a palladium catalyst using extremely large interfacial areas and the short path required for molecular diffusion in the very narrow channel space. This concept could be extended to other multiphase reactions that use gas-phase reagents such as oxygen and carbon dioxide. [ABSTRACT FROM AUTHOR]