Perhydropolysilazane-derived silica-polymethylmethacrylate hybrid thin films highly doped with spiropyran: Effects of polymethylmethacrylate on the hardness, chemical durability and photochromic properties

Polymethylmethacrylate (PMMA)-perhydropolysilazane (PHPS) hybrid thin films doped with spiropyran were prepared by spin-coating, which were then converted into 0.26-1.7 μm thick, spiropyran-doped PMMA-silica hybrid films by exposure treatment over aqueous ammonia. The spiropyran/(spiropyran + PHPS + PMMA) mass ratio was fixed at a high value of 0.2 so that the films exhibit visual photochromic changes in color, while the PMMA/(PMMA + PHPS) mass ratio, r, was varied. The spiropyran molecules in the as-prepared films were in merocyanine (MC) and spiro (SP) forms, with and without an optical absorption at 500 nm, at low (r ≤ 0.2) and high (r ≥ 0.4) PMMA contents, respectively. When PMMA content r was increased from 0 to 0.2, the degree of the MC-to-SP conversion on vis light illumination was enhanced, while at higher r's the spiropyran molecules underwent photodegradation. When the silica film (r = 0) was soaked in xylene under vis light, the spiropyran molecules were almost totally leached out, while not on soaking in the dark. On the other hand, no leaching occurred for the film of r = 0.2 either in the presence or absence of vis light. These suggest that the introduction of PMMA is effective in improving the chemical durability of the films, while the silica film (r = 0) is an interesting material with a photoresponsive controlled-release ability. The pencil hardness of the films decreased with increasing PMMA content, but remained over 9H at r ≤ 0.4.     

Induction of metallothionein synthesis by bismuth in cultured vascular endothelial cells

The accuracy and reliability of the TMJ Scale were originally determined in cross-validation studies on large, research-based patient samples. It had been assumed that the demographic characteristics and test responses of these research-based samples would be representative of the clinical population in which the TMJ Scale would ultimately find use. The present study on more than 10,000 patients that were evaluated for temporomandibular disorders in clinical practice demonstrates that the test scores, demographic variables, and the patterns of symptom severity that characterize the original TMJ Scale research sample accurately represent the general temporomandibular disorder patient population in which the TMJ Scale is now being used. The results suggest a high degree of confidence in the clinical efficacy of this assessment tool. The overall symptom severity of temporomandibular disorders was found to be normally distributed in the patient population. Women with temporomandibular disorders report a higher level of severity of all physical and psychological symptoms than men. This may explain the high female-to-male ratio in patients seeking treatment. However, a higher percentage of male temporomandibular disorder patients has clinically significant psychological and stress-related problems than do women. The severity and prevalence of symptoms associated with joint dysfunction and range of motion limitation are lower in older age groups, and the overall symptom severity of temporomandibular disorders is not higher in older age groups. However, the severity and prevalence of symptoms associated with joint dysfunction are greater in groups in which temporomandibular disorders have existed for longer durations, although pain levels do not follow this trend. There is also an association between time duration of the temporomandibular disorder and the severity of psychological problems and chronicity. Patients with chronic problems are symptomatically more impaired than those with acute problems.     

Recombinant cholera toxin B subunit acts as an adjuvant for the mucosal and systemic responses of mice to mucosally co-administered bovine serum albumin

We examined the mucosal adjuvant activity of recombinant cholera toxin B subunit (rCTB) produced by Bacillus brevis carrying pNU212-CTB by intranasal or oral co-administration of bovine serum albumin (BSA). Intranasal administration stimulated a high level of BSA-specific serum IgG antibody response and BSA-specific IgA antibody responses in the nasal and pulmonary lavages. Oral administration induced a moderate level of BSA-specific serum IgG antibody and a low level of BSA-specific IgA antibody in the large intestinal washes. These results show that CTB alone can act as an intranasal or oral delivery carrier; it also has strong adjuvant properties for stimulating serum IgG and mucosal IgA immune responses to unrelated, non-coupled antigens after intranasal or oral co-immunization.     

Hyperparathyroidism--comparison of flash imaging with spin echo MR imaging

MR images of the neck were prospectively studied in 19 patients with hyperparathyroidism. Fast low angle shot (FLASH) sequence was performed in addition to T1- and T2-weighted spin echo (SE) sequences. FLASH images were obtained with 320/12/20 degrees (TR/TE/flip angle) using presaturation technique. TE of 12 ms was chosen to eliminate high signal of fat tissue. In the evaluation of detectability, a combination of T1-weighted SE and FLASH images (T1WI + FLASH) was compared with a combination of T1- and T2-weighted SE images (T1WI + T2WI). MR imaging correctly depicted 20 of 30 abnormal glands on both T1WI + FLASH and T1WI + T2WI. FLASH imaging effectively eliminated high signal of fat tissue. Nineteen abnormal glands demonstrated higher signal than surrounding tissues on FLASH images, whereas 12 glands were high-intense on T2-weighted SE images. We conclude that FLASH imaging provides improved tissue contrast and anatomic delineation and, thus, may replace T2-weighted SE imaging in the neck.     

Activities of oxygen in liquid thallium and indium from electrochemical measurements

Modified coulometric titrations on the galvanic cell;O in liquid Tl or In/ZrO₂(+CaO)/Air, Pt, were performed at 973, 1073, and 1173 K to determine the oxygen activities in liquid thallium and liquid indium. The standard Gibbs energies of solution of oxygen in liquid thallium and liquid indium for l/2 O₂ →O (1 at. pct) were determined respectively to be δG‡(in Tl) = -22000 + 0.74T (±300) cal/g-atom = -92000 + 3.10T (±1300) J/g-atom, δG‡(in In) = -42450+ 3.30T (±350) cal/g-atom = -177600 + 13.8T (±1500) J/g-atom, where the reference state for dissolved oxygen was an infinitely dilute solution. It was reconfirmed that the apparent initial oxygen concentration observed in the range of very low oxygen concentration in liquid metal was attributed to the oxygen released from the solid electrolyte.     

Activities of oxygen in liquid copper and silver from electrochemical measurements

Modified coulometric titrations on the galvanic cell:O in liquid Cu or Ag / ZrO₂( + CaO) / Air, Pt, were performed to determine precisely the oxygen activities in liquid copper and silver in the range of relatively low oxygen concentration. The present experimental results were remarkably reproducible in comparison with the published data. The standard Gibbs energies of solution of oxygen in liquid copper and liquid silver for 1/2 O₂(l atm) → O(l at. pct) were determined respectively to be ΔG° (in Cu) = −18040 −0.03 T(K) (± 120) cal · g-atom−1 = −75500 −0.12 T(K)(± 500) J · g-atom−1, ΔG°(inAg)= -3860+ 1.56 T(K) (±90) cal · g-atom−1 = −16140 + 6.52 T(K)(±380) J · g-atom−1 where the reference state for dissolved oxygen was an infinitely dilute solution. The present value of the partial entropy of oxygen dissolved in liquid copper differs significantly from that suggested by many investigators. Further, the present equation for liquid copper has been found to be consistent with a correlation proposed previously by the present authors. The equation for liquid silver is in good agreement with the published ones.     

Modulation by endothelin-1 of tissue plasminogen activator and plasminogen activator inhibitor-1 release from cultured human vascular endothelial cells: interaction of endothelin-1 with cytokines

The interaction of endothelin-1 (ET-1) with either interleukin-1 beta (IL-1 beta) or tumor necrosis factor alpha (TNF alpha) on the release of tissue plasminogen activator antigen (t-PA:Ag) and plasminogen activator inhibitor-1 antigen (PAI-1:Ag) was investigated in a culture system of vascular endothelial cells derived from human umbilical vein. The t-PA:Ag release was significantly decreased by either IL-1 beta or TNF alpha; ET-1 intensified the suppressive effect of the cytokines. In contrast, PAI-1:Ag release was significantly increased by either IL-1 beta or TNF alpha; ET-1 significantly reduced the stimulatory effect of the cytokines. The data suggest that endothelial cell-mediated fibrinolysis may be modulated by ET-1.     

Radioactivation of structural material of the superconducting magnet for a fusion reactor

Radioactivation of five types of candidate steel alloys for the structural materials of superconducting toroidal field coils (TFC) of a D-T fusion reactor has been comparatively studied. As a result, the use of a high Mn steel in place of 316 SS is shown to reduce the dose rate at the He vessel of the TFC to ～ 1/3 the value with 316 SS at 1 day after shutdown, and to ～ 1/1000 at 10 years after shutdown. These reductions are mostly caused by the 0.28 wt% Co assumed to be included in 316 SS but none in the high Mn steel. Newly defined dose rate sensitivities of constituent elements are shown to be useful in identifying the cause of dose rate change brought on by the steel composition change. They can also be utilized in estimating the dose rate change brought on by the replacement of 316 SS with any new steel alloy with similar composition.     

Catalytic Performance of Aged Rh/CeO2–ZrO2 for NO–C3H6–O2 Reaction Under a Stoichiometric Condition

The activity of Rh/CeO₂ for NO reduction by C₃H₆ was gradually deceased by mixing with ZrO₂ until 68 mol%. Rh supported on CeO₂–ZrO₂ with higher OSC was found to show lower catalytic activity. High OSC of CeO₂–ZrO₂ would probably stabilize the surface of Rh in oxidized state, resulting in low activity and low efficiency of C₃H₆ utilization for NO reduction. In situ FT-IR spectroscopy suggested that mononitrosyl species such as Rh(NO)^δ? and Rh(NO)^δ+ are reaction intermediates in the NO–C₃H₆–O₂ reaction over Rh/CeO₂–ZrO₂ catalysts.