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Monocarboxylate transporter 8 (MCT8) deficiency is an X-linked recessive developmental disorder characterized by initially marked truncal hypotonia, later athetotic posturing, and severe intellectual disability caused by mutations in SLC16A2, which is responsible for the transport of triiodothyronine (T3) into neurons. We conducted a nationwide survey of patients with MCT8 deficiency to clarify their current status.Primary survey: In 2016-2017, we assessed the number of patients diagnosed with MCT8 deficiency from 1027 hospitals. Secondary survey: in 2017-2018, we sent case surveys to 31 hospitals (45 cases of genetic diagnosis), who responded in the primary survey. We asked for: 1) perinatal history, 2) developmental history, 3) head MRI findings, 4) neurophysiological findings, 5) thyroid function tests, and 5) genetic test findings.We estimated the prevalence of MCT8 deficiency to be 1 in 1,890,000 and the incidence of MCT8 deficiency per million births to be 2.12 (95 % CI: 0.99-3.25). All patients showed severe psychomotor retardation, and none were able to walk or speak. The significantly higher value of the free T3/free T4 (fT3/fT4) ratio found in our study can be a simple and useful diagnostic biomarker (Our value 11.60 ± 4.14 vs control 3.03 ± 0.38). Initial white matter signal abnormalities on head MRI showed recovery, but somatosensory evoked potentials (SEP) showed no improvement, suggesting that the patient remained dysfunctional.For early diagnosis, including in mild cases, it might be important to consider the clinical course, early head MRI, SEP, and fT3/fT4 ratio.

Panayiotopoulos syndrome (PS) is a common benign epilepsy in childhood, characterized by predominantly autonomic symptoms such as emesis, pallor, and seizures, which are often prolonged. In an emergency room (ER), particularly when unconsciousness is prolonged, differentiating PS from acute encephalopathy is challenging. In this study, we aimed to elucidate the differences in clinical features of patients with PS and acute encephalopathy who visited our ER.We retrospectively reviewed 18 patients who were transferred to our ER because of status epilepticus later diagnosed as PS, and 30 patients with acute encephalopathy, between July 2012 and July 2017. We compared patient demographics, clinical characteristics, and treatment.Most patients (90%) with acute encephalopathy had convulsive seizures of greater than or equal to 15 min, whereas only three patients (17%) with PS had convulsive seizures of greater than or equal to 15 min (P 0.001). In addition, seizures were treatable in all patients with PS with a small dose of midazolam (0.1 mg/kg), but all patients with acute encephalopathy required midazolam at 0.3 mg/kg or more (P 0.001). More patients with PS had autonomic symptoms compared to those with acute encephalopathy (e.g., vomiting [78% vs. 3%, P 0.001]). Non-convulsive status epilepticus was observed in 22% of PS patients, but not in any acute encephalopathy patients. In contrast, fever was observed in all patients with acute encephalopathy (100%), but less frequently in those with PS (11%, P 0.001).PS was characterized by 1) convulsive seizures shorter than 15 min, 2) seizures treatable with small doses of midazolam, and 3) autonomic symptoms. PS could be differentiated from acute encephalopathy in the early stages of the syndrome.

We summarize the long-term motor outcome and disability level in a cluster of pediatric patients with acute flaccid myelitis (AFM) associated with the enterovirus D68 outbreak in 2015.This is a nationwide follow-up questionnaire analysis study. Clinical data including the motor function (manual muscle strength test) and other neurological symptoms were collected at the acute (nadir), recovery (six months), and chronic (three years) stages. We use the Barthel index, which measures 10 variables describing activity of daily living and mobility to assess the disability level.Clinical data of 33 patients with AFM (13 females, 20 males; median age = 4.1 years) were available. Among patients with tetraplegia or triplegia, paraplegia, and monoplegia at the acute stage, two of seven, four of thirteen, and two of thirteen exhibited complete recovery without paralysis; of those five of seven, eight of thirteen, and two of thirteen showed improvement with lesser limb involvement at the chronic stage, respectively. Nine patients (27%) demonstrated improvement at the recovery-to-chronic period. All six patients with positive isolation of enterovirus D68 from biological samples at the acute stage showed persistent motor deficits. Other neurological findings had better prognosis than motor weakness. Better Barthel index score at the chronic stage was observed (P 0.001; median difference [95% confidence interval], 53 [40 to 63]), implying an improved disability level even in patients with persistent motor deficits.AFM has a high rate of persistent motor deficits showing one- to two-limb paralysis. Disability level of patients with AFM, however, generally improved at the three-year time point.

This study highlights the importance of heat release rate in low-temperature oxidation (LTO) on non-uniform end-gas autoignition and strong pressure wave generation, which are substantially relevant to knocking combustion. The simulations are conducted using the compressible Navier–Stokes equations with detailed transport and chemical kinetics models in a one-dimensional constant-volume reactor. Four fuel/air stoichiometric mixtures, n-butane, i-octane, n-heptane, and dimethyl ether (DME)/air mixtures, are simulated. The results show that larger knocking intensities are produced with n-heptane and DME in their negative temperature coefficient (NTC) regimes because of the stronger non-uniformity of end-gas autoignition. The non-uniformity of end-gas autoignition is enhanced by a pressure wave disturbance that is caused by the rapid temperature rise of the end-gas region in LTO. In particular, the high heat release rate with the DME/air mixture generates a distinct pressure wave disturbance in the reactor, which considerably enhances the non-uniformity of end-gas autoignition through the reflection of the wave at the wall. In contrast, the heat release rate in the n-heptane case is milder than that in the DME case, and therefore, the knocking intensity in the n-heptane case is smaller compared to that of DME due to less enhancement of the non-uniform end-gas autoignition. No large knocking intensities are produced with n-butane and i-octane, which have weak NTC, because of the absence of a temperature rise in LTO. Thus, this study concludes that the high heat release rate in LTO and the generated pressure wave disturbance play a significant role in the generation of large knocking intensities through the enhancement of non-uniform end-gas autoignition.

The present study proposes a localized thickened flame (LTF) model for the accurate prediction of flame propagation and autoignition timing. The unresolved-scale terms appeared in spatially-filtered governing equations due to thin flame structures are constructed under a physical constraint in which laminar flame speed is maintained. A high-order derivative is introduced to dynamically localize the effects of the LTF in the regions of unresolved propagating flame. The model is also designed such that the thickened flame is resolved by the same number of grid points for any grid size used. Therefore, a user-specified constant in the model does not need to be adjusted depending on the employed grid size. Laminar flame propagation problems are used to validate the performance of the proposed LTF model and determine the appropriate value of the user-specified constant. The results using a one-dimensional constant-volume reactor demonstrate that the LTF successfully captures the accurate flame propagation behaviors under elevated pressure conditions, while not affecting the end-gas autoignition timing, even on relatively coarse grid resolutions. The high-order derivative in the LTF serves as a dynamic parameter for detecting the thinning flame under elevated pressure conditions.

The present study addresses effects of pressure wave disturbance on end-gas autoignition behavior and subsequent pressure wave development, which are of particular interest for understanding a fundamental process of knocking combustion in spark-assisted ignition engines. Such pressure wave disturbance is initiated by a compression wave generated from spark-like ignition and continuously exists in a combustion chamber. The investigation is conducted through a direct numerical simulation with a 1-D constant volume reactor, where the compressible Navier–Stokes equations are solved with detailed reaction mechanisms of n − C 7 H 16 and n − C 4 H 10 /air mixtures. The width of an ignition kernel parametrically changes in order to control the strength of an initial compression wave and thus pressure wave disturbance. The result showed that stronger compression waves with larger kernel widths enhance the progress of the autoignition process at the wall through the transient increase in pressure and temperature due to the wave reflection. Consequently, stronger pressure waves such as a developing detonation are generated with the enhanced inhomogeneous end-gas autoignition starting from the wall. In contrast, weak pressure wave disturbance produces no strong pressure waves due to the lower inhomogeneity of autoignition timing in an end-gas region. An analysis with temperature variation in an end-gas region indicates that cool flame generation helps maintain the superiority of the wall for earlier autoignition through the heat release at an earlier stage. Therefore, a stronger pressure wave associated with inhomogeneous end-gas autoignition is likely generated around 650 K in the case of an n − C 7 H 16 /air mixture, which corresponds to a distinct peak generation of knocking intensity in the negative temperature coefficient regime. For lower temperature conditions such as 500 K, the end-gas autoignition first takes place in a region away from the wall. This is because the initially induced temperature inhomogeneity in the end-gas region is considerably weakened due to wave interactions and dissipation effects during longer ignition delay times. Thus, multiple end-gas points including the wall can become a preferred point for earlier end-gas autoignition, resulting in a variation of end-gas autoignition locations. The result for an n − C 4 H 10 /air mixture is finally shown and the difference from that for the n − C 7 H 16 /air mixture is highlighted.

The present study deals with the mechanisms for the hot-spot formation and pressure wave development associated with end-gas autoignition during knocking combustion of n -heptane/air mixture. The discussion is based on a one-dimensional (1-D) direct numerical simulation, where the compressible Navier–Stokes equations are solved with a detailed chemical kinetic mechanism of n -heptane, involving 373 species and 1071 reactions. The result demonstrates that the first trigger for a hot-spot formation is a compression wave generated by forced autoignition of a hot kernel and its reflection at a wall. The wall reflection of the propagating compression wave periodically produces an instantaneous temperature increase, which leads to the production of a larger amount of chemical species compared to that of other end-gas points. This non-uniform progress of chemical reaction process continues to exist at the wall, although the temperature increase is transient, resulting in faster autoignition and pressure wave generation at the wall. Thus, an important aspect of observing chemistry behaviors rather than temperature is demonstrated on the mechanism of hot-spot formation. The present study further addresses the reactivity of hot-spots on the relevance to pressure wave developments, wherein a zero-dimensional (0-D) ignition problem with pulsed compression waves is introduced. The higher reactivity of n -heptane/air mixture against pulse waves is observed with the faster ignition delay times in lower and higher initial temperature conditions. Conversely, the result at initial temperatures of 750—800 K indicates the lower reactivity with no significant effects of pulse waves on the ignition delay times. This is connected with the fuel characteristics of a negative temperature coefficient. Thus, in the 1-D simulations, a hot-spot with the high reactivity enhances spatial temperature difference in the end-gas region, leading to strong pressure wave generations. In contrast, a hot-spot with the low reactivity suppresses the pressure wave development with little spatial variation in temperature. The result demonstrates a significant aspect of hot-spot formation and reactivity on pressure wave development during knocking combustion.

The diffusive-thermal effect plays an important role in the intrinsic instability of premixed flames. A two-dimensional direct numerical simulation of the propagation of premixed hydrogen–air flames was performed using a detailed chemical kinetics model. The cellular behavior of a lean hydrogen–air flame was analyzed on the basis of its chemical structure. The primary consequence of the diffusive-thermal effect was found to be a change in the buildup process of reactive intermediates by the chain reaction mechanism at the preheat zone. The resultant chemical structure at the main reaction zone can be explained by the local composition change of the gas flowing into the reaction zone from the preheat zone.

Febrile infection-related epilepsy syndrome (FIRES), or acute encephalitis with refractory, repetitive partial seizures (AERRPS), is an epileptic encephalopathy beginning with fever-mediated seizures. The etiology remains unclear. To elucidate the genetic background of FIRES/AERRPS (hereafter FIRES), we recruited 19 Japanese patients, genotyped polymorphisms of the IL1B , IL6 , IL10 , TNFA , IL1RN , SCN1A and SCN2A genes, and compared their frequency between the patients and controls. For IL1RN , the frequency of a variable number of tandem repeat (VNTR) allele, RN2, was significantly higher in the patients than in controls ( p =0.0067), and A allele at rs4251981 in 5′ upstream of IL1RN with borderline significance (p =0.015). Haplotype containing RN2 was associated with an increased risk of FIRES (OR 3.88, 95%CI 1.40–10.8, p =0.0057). For SCN1A , no polymorphisms showed a significant association, whereas a missense mutation, R1575C, was found in two patients. For SCN2A , the minor allele frequency of G allele at rs1864885 was higher in patients with borderline significance ( p =0.011). We demonstrated the association of IL1RN haplotype containing RN2 with FIRES, and showed a possible association of IL1RN rs4251981 G>A and SCN2A rs1864885 A>G, in Japanese patients. These preliminary findings suggest the involvement of multiple genetic factors in FIRES, which needs to be confirmed by future studies in a larger number of FIRES cases.

Objective Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is a childhood encephalopathy following severe febrile seizures. The pathogenesis of AESD is considered to be fever-induced seizure susceptibility and excitotoxicity, which may be caused by sodium channel dysfunction in some cases. Here we studied whether mutations in genes encoding sodium channels, SCN1A and SCN2A , predispose children to AESD. Methods We recruited 92 AESD patients in a nationwide survey of acute encephalopathy in Japan from 2008 to 2011. We collected their genomic DNA samples, and sequenced the entire coding region of SCN1A and SCN2A . Results Five out of 92 patients (5.4%) had missense mutations either in SCN1A or SCN2A . After a preceding infection with fever, all the patients showed status epilepticus at the onset. Hemiconvulsion–hemiplegia was recognized in three patients during the acute/subacute phase. One patient had taken theophylline for the treatment of bronchial asthma just before the onset of AESD. Familial history was not remarkable except one patient with a SCN1A mutation (G1647S) whose mother had a similar episode of AESD in her childhood. A different substitution (G1674R) at the same amino acid position, as well as two other SCN1A mutations found in this study, had previously been reported in Dravet syndrome. Another SCN1A mutation (R1575C) had been detected in other types of acute encephahlitis/encephalopathy. One patient had SCN2A mutation, F328V, which had previously been reported in Dravet syndrome. Another SCN2A mutation, I172V, was novel. None of the patients were diagnosed with Dravet syndrome or genetic (generalized) epilepsy with febrile seizure plus in the following-up period. Conclusions Mutations in SCN1A and SCN2A are a predisposing factor of AESD. Altered channel activity caused by these mutations may provoke seizures and excitotoxic brain damage.

This paper addresses issues in high-fidelity numerical simulations of transcritical turbulent flows at supercritical pressure. The proposed strategy builds on a tabulated look-up table method based on REFPROP database for an accurate estimation of non-linear behaviors of thermodynamic and fluid transport properties at the transcritical conditions. Based on the look-up table method we propose a numerical method that satisfies high-order spatial accuracy, spurious-oscillation-free property, and capability of capturing the abrupt variation in thermodynamic properties across the transcritical contact surface. The method introduces artificial mass diffusivity to the continuity and momentum equations in a physically-consistent manner in order to capture the steep transcritical thermodynamic variations robustly while maintaining spurious-oscillation-free property in the velocity field. The pressure evolution equation is derived from the full compressible Navier-Stokes equations and solved instead of solving the total energy equation to achieve the spurious pressure oscillation free property with an arbitrary equation of state including the present look-up table method. Flow problems with and without physical diffusion are employed for the numerical tests to validate the robustness, accuracy, and consistency of the proposed approach.

Hydrazine (N2H4)/nitrogen tetroxide (NTO) co-flowing plane jets were simulated to explore the hypergolic ignition processes and flame structures in N2H4/NTO bipropellant thrusters. The Navier–Stokes equations with a detailed chemical kinetics mechanism were solved in a manner of direct numerical simulation to reveal the influence of the distinct chemical reaction, i.e., hydrogen abstraction by nitrogen dioxide (NO2) and the thermal decomposition of N2H4. In the ignition processes, the hydrogen abstraction sequence played a significant role in preheating the mixture gases. Further, the ignition eventually occurred in the region where both N2H4 and NTO were sufficiently supplied for preheating. Hence, the ignition position and delay strongly depended on the fluid-mixing conditions. After the flames reached a steady state, the combustion flames uniquely comprised two types of flames, the outer diffusion flame and the inner decomposition flame. The outer diffusion flame came from the oxidization by NTO. The inner decomposition flame was caused and maintained by the heat transfer from the outer diffusion flame and a high rate of heat release from the thermal decomposition of N2H4. Because of the decomposition flame, the decomposition products such as NH3 and H2 were the major constituents of the downstream combustion gases., 資料番号: PA1510062000

A two-dimensional (2-D) simulation of spontaneous ignition of high-pressure hydrogen in a length of duct is conducted to explore ignition mechanisms. The present study adopts a 2-D rectangular duct and focuses on effects of the initial diaphragm shape on spontaneous ignition. The Navier–Stokes equations with a detailed chemical kinetics mechanism are solved in a manner of direct numerical simulation. The detailed mechanisms of spontaneous ignitions are discussed for each initial diaphragm shape. For a straight diaphragm, ignition only occurs near the wall owing to the adiabatic wall condition, while three ignition events are identified for a greatly deformed diaphragm: ignition due to reflection of leading shock wave at the wall, hydrogen penetration into shock-heated air near the wall, and deep penetration of hydrogen into shock-heated air behind the leading shock wave.

An interface-capturing method using a high-order central difference scheme is presented for simulations of compressible multicomponent flows. The present method adds consistent numerical diffusion terms to robustly capture interface discontinuities, while maintaining the velocity, pressure, and temperature equilibriums at interfaces. Analysis of the numerical errors generated at the interfaces leads to a proposal of new consistent numerical diffusion terms. The method solves a fully conservative form of the total mass, momentum, total energy, and species-mass, and an additional advection form of the specific heats ratio to preserve the pressure oscillation-free property at the interfaces. Several one- and two-dimensional problems are used to verify the proposed method.

We present characteristic magnetic resonance imaging (MRI) features in a pediatric female patient with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Muscle weakness developed at 8 years old and fluctuated during the clinical course over 7 years. Electrophysiological studies showed a demyelination pattern with moderately delayed nerve conduction velocity, as well as dispersion phenomenon. MRI showed marked changes in thickening of the spinal nerve roots and their peripheral nerves in the lumber and brachial plexuses, as well as in the bilateral trigeminal nerves. It is suggested that these MRI features are characteristic and strongly supportive of the diagnosis of CIDP with a prolonged clinical course.

This study presents a strategy for simulations of cryogenic single-species jets under supercritical pressure conditions. In this strategy, a pressure evolution equation is introduced and numerical diffusion terms are consistently constructed in order to maintain the pressure and velocity equilibriums at fluid interfaces. By taking the idea of the equilibrium, the interfaces with high density and temperature ratio are robustly captured without the generation of spurious oscillations, while a high-order central differencing scheme resolves the flow fields. The present method preserves the mass and momentum conservation properties, while the poor energy conservation property is recognized. The one-dimensional interface advection and two-dimensional cryogenic jet mixing problems demonstrate the superiority and robustness of the present method over a conventional fully conservative approach.

Heterotrimeric G proteins, composed of α, β, and γ subunits, can transduce a variety of signals from seven-transmembrane-type receptors to intracellular effectors. By whole-exome sequencing and subsequent mutation screening, we identified de novo heterozygous mutations in GNAO1, which encodes a Gαo subunit of heterotrimeric G proteins, in four individuals with epileptic encephalopathy. Two of the affected individuals also showed involuntary movements. Somatic mosaicism (approximately 35% to 50% of cells, distributed across multiple cell types, harbored the mutation) was shown in one individual. By mapping the mutation onto three-dimensional models of the Gα subunit in three different complexed states, we found that the three mutants (c.521A>G [p.Asp174Gly], c.836T>A [p.Ile279Asn], and c.572_592del [p.Thr191_Phe197del]) are predicted to destabilize the Gα subunit fold. A fourth mutant (c.607G>A), in which the Gly203 residue located within the highly conserved switch II region is substituted to Arg, is predicted to impair GTP binding and/or activation of downstream effectors, although the p.Gly203Arg substitution might not interfere with Gα binding to G-protein-coupled receptors. Transient-expression experiments suggested that localization to the plasma membrane was variably impaired in the three putatively destabilized mutants. Electrophysiological analysis showed that Gαo-mediated inhibition of calcium currents by norepinephrine tended to be lower in three of the four Gαo mutants. These data suggest that aberrant Gαo signaling can cause multiple neurodevelopmental phenotypes, including epileptic encephalopathy and involuntary movements.

This study proposes an approach for simulations of cryogenic fluid mixing under supercritical pressures using high-order schemes. In this approach, we introduce a pressure evolution equation and consistently construct numerical diffusion terms to maintain the velocity and pressure equilibriums at fluid interfaces. The interfaces with high density and temperature ratio are successfully captured without the generation of spurious oscillations, while a high-order central differencing scheme resolves the flow fields. The present method preserves the mass and momentum conservation properties, while the poor energy conservation property is recognized. The one-dimensional single and multi-species interface advection and two-dimensional cryogenic jet mixing problems demonstrate the superiority and robustness of the present method over a conventional fully conservative method.

A front-tracking method for compressible multi-fluid flows is presented, where marker points are used both for tracking fluid interfaces and also for constructing the Riemann problem on the interfaces. The Riemann problem between the two fluid phases (defined in the interface normal direction) is solved using the exact Riemann solver on the marker points. The solutions are projected onto fixed grid points and then extrapolated into the corresponding ghost-fluid regions, to be used as boundary conditions. Each fluid phase is solved separately as in the ghost-fluid method. The proposed procedures, especially the projection of the exact Riemann solutions onto the fluid grids, are designed to be simple and consistent in any spatial dimensions. Several multi-fluid problems, including the breakup of a water cylinder induced by the passage of a shock wave were computed in order to demonstrate the capability of the proposed method.

A front-tracking/ghost-fluid method is introduced for simulations of fluid interfaces in compressible flows. The new method captures fluid interfaces using explicit front-tracking and defines interface conditions with the ghost-fluid method. Several examples of multiphase flow simulations, including a shock-bubble interaction, the Richtmyer-Meshkov instability, the Rayleigh-Taylor instability, the collapse of an air bubble in water and the breakup of a water drop in air, using the Euler or the Navier-Stokes equations, are performed in order to demonstrate the accuracy and capability of the new method. The computational results are compared with experiments and earlier computational studies. The results show that the new method can simulate interface dynamics accurately, including the effect of surface tension. Results for compressible gas-water systems show that the new method can be used for simulations of fluid interface with large density differences.

Isothermal deep-level transient spectroscopy (DLTS) with a single pulse has been used to study the transformation behavior of a metastable defect labeled EM1 ( E c −0.29 eV) which is observed in n-type silicon implanted with hydrogen ions at 88 K and subsequently heated to room temperature. It is found that EM1 shows a decrease in isothermal DLTS peak height with filling pulse duration time in the range from 1 ms to 1000 s. Isothermal DLTS allows us to detect another metastable defect labeled EM2 ( E c −0.41 eV) as well as EM1 at the same temperature and reveals a corresponding increase in EM2 peak height with filling time. This indicates that EM1 filled with electrons is transformed into EM2 during application of filling pulse.

Adsorption of bovine serum albumin (BSA) from aqueous solution to muscovite mica has been investigated through the measurements of two quantities: (1) the adsorbance, i.e. adsorbed mass per unit area measured as a function of incubation time by means of a Mettler UM3 ultramicrobalance; and (2) the contact angle of water droplets resting on the adsorbed BSA layer to know the degree of surface covering. The protein concentration explored was 0.002 and 0.01 mg ml −1 in aqueous solution at pH 5.8. The temperature was kept constant at 25 °C. The following results have been obtained in the present study. (1) The initial rate of adsorption is more rapid than generally accepted. The surface of mica is completely covered by adsorbed BSA molecules within 10 min even for a dilute solution at a concentration 0.002 mg ml −1 . (2) At a stage where the surface covering is completed, the adsorbance levels off at a steady value, which is approximately equal to mass per unit area of side-on monolayer. It concludes from this result that BSA molecules are adsorbed side-on directly onto mica surface to form a side-on monolayer. (3) If the adsorption is prolonged, the adsorbance exceeds the mass per unit area of side-on monolayer owing to the adsorption of BSA molecules onto the side-on monolayer already formed. This fact indicates the occurrence of multilayer adsorption of BSA.

The effect of halide anions on pyridine- d 5 adsorbed on Au(111) electrode has been studied in neutral solutions containing F − , Cl − , and Br − by IRAS and differential capacity measurement. In the NaF solution, N-bonded pyridine increases up to 0.1 V, and a new adsorbed state due to the N-bonded type grows at positive potentials. In the NaCl solution, the N-bonded type grows at all of adsorbed potential except for the appearance of the new adsorbed state at 0.2 V. In the NaBr containing solution, the new adsorbed state is not observed. In the NaCl and NaBr solutions, the total amount of the N-bonded pyridine is suppressed at positive potentials. We propose that the new band is attributed to an ordered layer of the N-bonded pyridine on the Au(111) electrode, and that the formation of the ordered layer is inhibited by the adsorption of Cl − and Br − .

Pyrazine adsorbed on Au(111), Au(100) and Au(110) electrodes in 0.1 M NaF containing 5 mM pyrazine have been investigated by using in-situ infrared spectroscopy. For each of the three electrodes, an in-plane ring symmetrical vibration due to vertically adsorbed pyrazine was observed around 1045 cm−1, which was accompanied by a loss in the in-plane ring asymmetrical vibration at 1419 cm−1 due to dissolved pyrazine. For the Au(111), the behavior of the 1419 cm−1 band intensities corresponding to the total amount of adsorbed pyrazine was coincident with previous results of the Gibbs surface excess investigated by using of chronocoulometry. The behavior of 1045 cm−1 band intensity as a function of the applied potential was similar to that of the 1419 cm−1 band for the Au(111) and Au(100). We propose that the tilt orientation is present at negative potentials and the vertical orientation increases as the potential becomes more positive. For all the electrodes, a new band appeared around 1035 cm−1 for positive potentials, which was assigned to an in-plane ring symmetrical vibration, as for the 1045 cm−1 case. We propose that the new band is associated with some adsorption behavior such as a change in the vertically adsorbed pyrazine orientation.

The objective of this study was to estimate colon‐specific delivery of insulin and (Asu 1,7 )eel‐calcitonin using novel azopolymer‐coated pellets. In vitro drug‐release experiments from the azopolymer‐coated pellets containing fluorescein isothiocyanate dextran (MW 4400; FD‐4) were carried out by the Japanese Pharmacopoeia (J.P.) XIII rotating basket method with some slight modifications. Little release of FD‐4 from the pellets was observed in phosphate buffered saline. However, the release of FD‐4 was markedly increased in the presence of rat cecal contents. The intestinal absorption of insulin and (Asu 1,7 )eel‐calcitonin after oral administration of the azopolymer‐coated pellets containing these peptides with camostat mesilate was evaluated by measuring the hypoglycemic and hypocalcemic effects, respectively. A slight decrease in plasma glucose levels was observed following the oral administration of these pellets containing 12.5 IU of insulin compared with the same dose of insulin solution. Camostat mesilate, a protease inhibitor that is incorporated with insulin in these pellets, further decreased the plasma glucose levels in a dose‐dependent manner. Similar results were also obtained with the oral administration of pellets containing (Asu 1,7 )eel‐calcitonin. These findings suggest that azopolymer‐coated pellets may be useful carriers for the colon‐specific delivery of peptides including insulin and (Asu 1,7 )eel‐calcitonin. © 2001 Wiley‐Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 90:89–97, 2001

This paper describes an experimental study of ultrathin films of polystyrene adsorbed from cyclohexane at the θ-temperature (307.5 K) onto molecularly smooth surfaces of mica. The amount adsorbed is determined directly using a microbalance (sensitivity ∼-10 −6 g wt) so that adsorbances on the order of 0.2 mg m −2 can be detected on mica sheets of area 5 x 10 −3 m 2 . The films may then be floated offthe mica onto a water surface using a suitable markel (Chinese ink) to delineate the shape and area of the transferred film. These results are used to discuss the way in which film structure may vary with the adsorbance of polymer on mica.

A novel method has been developed for the study of the polymer adsorption at the mica-solution interface. The amount of polymer adsorbed on mica has been determined by the direct measurement of the weight change of mica sheets due to the polymer adsorption. For this purpose, a fused quartz torsion microbalance of sensitivity ⋍10−6 g wt has been constructed, which is capable of detecting the change in adsorbance by 0.2 mg m−2 on mica sheets 5 × 10−3 m2 (50 × 50 mm) in total area. This paper gives the detailed description of the experimental apparatus and procedure. An example is shown of the application of this method to the determination of the kinetics of adsorption and desorption of polystyrene at the mica-cyclohexane interface. The following points have been discussed on the basis of the results obtained: (i) adsorbance of polystyrene on mica at saturation, (ii) irreversibility of polymer adsorption, and (iii) occurrence of multilayer adsorption.