Free-standing,roll-able,and transparent silicone polymer film prepared by using nanoparticles as cross-linking agents

A free-standing, roll-able, and transparent silicone-based polymer film with a tensile modulus of ca. 7.8 MPa and strain at the break point of 0.76% was successfully prepared by reaction between a reactive silicone oligomer with methyl- and methoxy-side groups and hydrophilic SiO₂ nanoparticles. First, SiO₂ nanoparticles were grafted with silicone chains by a controlled wet chemical sol–gel-type reaction with the reactive oligomers. The solvent of the resulting solution was evaporated to form a viscous suspension, casted into a film, and finally heat-treated at 100 °C and 150 °C. A hydrolysis and condensation reaction among silicone-grafted SiO₂ nanoparticles and free silicone oligomers in the final heat treatment resulted to produce free-standing, roll-able, and transparent silicone-based polymer film. The fact that the silicone film cannot be synthesized without the presence of SiO₂ nanoparticles suggests that these nanoparticles act as cross-linking agents of silicone components providing the improved mechanical properties to the composite film. The rate-controlled mixing and heating of the SiO₂ aqueous/alcohol suspension and the silicone oligomer/alcohol solution was found to be the key step in the synthesis of the free-standing transparent film. While rapid addition/mixing resulted in a fragile and opaque film, a transparent material was achieved when those solutions were slowly mixed. The effect of the synthesis process on the macroscopic and microscopic properties of the prepared films is discussed along with their formation mechanism.     

Elution of sodium caseinate from agar-based gel matrixes in simulated gastric fluids

Elution of sodium caseinate from agar/psyllium composite gels was investigated in simulated gastric fluids to determine predominant mechanical parameters of gels for the elution kinetics and to predict the kinetics using the parameters. When the concentration of agar was fixed at 0.5% in the composite gels, elastic moduli determined by creep tests decreased with increasing concentration of psyllium, while viscosities increased. Compression load upon syringing through an enteral tube increased with increasing concentration of psyllium, whereas the surface-volume diameter d_3,2 of gel particles after syringing decreased. The elution kinetics of sodium caseinate from cylindrical gels was described using two different diffusion coefficients; D₁ and D₂ (D₁ > D₂) and the diameter of gels. Both diffusion coefficients decreased with increasing concentration of psyllium, resulting in 1.9 × 10⁻⁶ (for D₁) and 6.7 × 10⁻⁸ (for D₂) cm²/min by 1.5% addition, which corresponded to approx. 30% and 45% of the control (i.e., 0% psyllium), respectively. The fraction ratio of sodium caseinate having D₁ was not sensitive to psyllium concentration; approx. 80%–85% in the concentration range tested. D₁ was inversely proportional to viscosities determined by creep tests, particularly one from the Voigt body η₁ in the 4-element mechanical model. When cube gels were divided into smaller ones without changing the total volume, elution rates were inversely proportional to the cube length, where the diffusion coefficients did not change. The elution kinetics of sodium caseinate from the gel matrixes was anticipated using η₁ of gels before syringing and d_3,2 of gel particles after syringing when the usage of gels for percutaneous endoscopic gastrostomy is assumed.     

Nanostructured Fe-Pd thin films for thermoelastic shape memory alloys—electrochemical preparation and characterization

Nanostructured Fe-Pd thin films with about 30 at.% Pd have been successfully synthesized on the substrates of Pt buffer layer/Cr seed layer/Si by an electrodeposition process from a plating bath containing ammonium tartrate, citric acid and ammonia solution as complexing agents. Results clearly show that the as-deposited films with body-centered cubic structure were transformed into face-centered cubic structure by heating at 900 °C for 45 min followed by quenching into iced water. The in situ X-ray diffraction analysis results indicate that the quenched film with 29.8 at.% Pd undergoes a reversible thermoelastic austenite-to-martensite transformation with a narrow temperature hysteresis and a martensite transformation temperature of about −30 °C. The present study demonstrates the effectiveness of electrodeposition for synthesizing nanostructured Fe-Pd thin films for the application of low-temperature-type thermoelastic shape memory alloys.     

π-Conjugated poly(pyrimido[5,4-d]pyrimidine-2,6-diyl)s with two different alkylamino groups: Synthesis,chemical properties,and structure

New π-conjugated pyrimidopyrimidine polymers with two different alkylamino groups at C4 and C8 positions, PPympym(4-NH-n-C₈H₁₇-8-NHR) (R = n-C₄H₉, n-C₆H₁₃, n-C₁₂H₂₅, and n-C₁₆H₃₃), were prepared by dehalogenation polycondensation using nickel zerovalent complex in high yield. The obtained polymers were partly soluble in organic solvents such as chloroform. A chloroform soluble part of PPympym(4-NH-n-C₈H₁₇-8-NH-n-C₁₆H₃₃) showed a number-average molecular weight of about 3,000 in GPC analysis. UV–vis spectra of the polymers in CHCl₃ showed a π–π^* absorption peak at about 450 nm, and the peak position shifted by 30 nm to a longer wavelength in film. The polymers showed photoluminescence both in solution and in film. Cast films of the polymers were electrochemically reduced at about ?2.3 V vs. Ag⁺/Ag. XRD patterns of the polymers revealed the polymers took an end-to-end packed structure.     

Preparation and properties of titania-Cs2.5H0.5PW12O40 hybrid films

Using continuous coating with Si-alkoxide as a binder, Cs_2.5H_0.5PW₁₂O₄₀ (Cs2.5) powder was prepared and immobilized onto a Pyrex glass plate. The Cs2.5 coating possessed an acid site on the film surface. Translucent TiO₂-Cs2.5 hybrid films were prepared by laminating TiO₂ films with holes on the Cs2.5 coating using phase-separation of alkoxide. Photocatalytic decomposition of 1,4-dioxane in water revealed that the holes serve as adsorption fields for ethylene glycol diformate, an intermediate with poor affinity to TiO₂. The TiO₂-Cs2.5 hybrid films produced by this process are candidates for purification of water containing several chemicals with a slow decomposition rate in photocatalysis.     

Comparative study of homogeneous solvents for the esterification crosslinking of cellulose with 1,2,3,4‐butanetetracarboxylic dianhydride and water absorbency of the reaction products

Superabsorbent hydrogels were prepared via esterification crosslinking of cellulose with 1,2,3,4‐butanetetracarboxylic dianhydride (BTCA) in three solvent systems: lithium chloride (LiCl)/N‐methyl‐2‐pyrrolidinone (NMP), LiCl/N,N‐dimethylacetamide (DMAc), and tetrabutylammonium fluoride/dimethyl sulfoxide (TBAF/DMSO). The absorbency of the hydrogels was strongly dependent on the BTCA feed to cellulose ratio as well as the nature of the solvent system used. The rate of cellulose esterification was enhanced in TBAF/DMSO relative to the other systems, and the highest water absorbency of the hydrogels (987 g g^?1 polymer) was also achieved using this system. The hydrogels obtained in the TBAF/DMSO system had a similar degree of both crosslinking and grafting, indicating that both reactions were promoted to the same extent in this solvent, whereas crosslinking was preferentially enhanced over grafting in the LiCl/NMP and LiCl/DMAc systems. The difference in the composition of the hydrogels was attributed to the difference in the electronegativity of the fluoride and chloride anions in these solvents. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Wind tunnel study on wind and turbulence intensity profiles in wind turbine wake

In recent years, there has been a rapid development of the wind farms in Japan. It becomes very important to investigate the wind turbine arrangement in wind farm, in order that the wake of one wind turbine does not to interfere with the flow in other wind turbines. In such a case, in order to achieve the highest possible efficiency from the wind, and to install as many as possible wind turbines within a limited area, it becomes a necessity to study the mutual interference of the wake developed by wind turbines. However, there is no report related to the effect of the turbulence intensity of the external flow on the wake behind a wind turbine generated in the wind tunnel. In this paper, the measurement results of the averaged wind profile and turbulence intensity profile in the wake in the wind tunnel are shown when the turbulence intensity of the external wind was changed. The wind tunnel experiment is performed with 500mm-diameter two-bladed horizontal axis wind turbine and the wind velocity in wake is measured by an I-type hot wire probe. As a result, it is clarified that high turbulence intensities enable to the entrainment of the main flow and the wake and to recover quickly the velocity in the wake.     

ATM: Functions of ATM Kinase and Its Relevance to Hereditary Tumors

Ataxia–telangiectasia mutated (ATM) functions as a key initiator and coordinator of DNA damage and cellular stress responses. ATM signaling pathways contain many downstream targets that regulate multiple important cellular processes, including DNA damage repair, apoptosis, cell cycle arrest, oxidative sensing, and proliferation. Over the past few decades, associations between germline ATM pathogenic variants and cancer risk have been reported, particularly for breast and pancreatic cancers. In addition, given that ATM plays a critical role in repairing double-strand breaks, inhibiting other DNA repair pathways could be a synthetic lethal approach. Based on this rationale, several DNA damage response inhibitors are currently being tested in ATM-deficient cancers. In this review, we discuss the current knowledge related to the structure of the ATM gene, function of ATM kinase, clinical significance of ATM germline pathogenic variants in patients with hereditary cancers, and ongoing efforts to target ATM for the benefit of cancer patients.     

Pannexin 1-Mediated ATP Signaling in the Trigeminal Spinal Subnucleus Caudalis Is Involved in Tongue Cancer Pain

Pain is one of the most severe concerns in tongue cancer patients. However, the underlying mechanisms of tongue cancer pain are not fully understood. We investigated the molecular mechanisms of tongue cancer-induced mechanical allodynia in the tongue by squamous cell carcinoma (SCC) inoculation in rats. The head-withdrawal threshold of mechanical stimulation (MHWT) to the tongue was reduced following SCC inoculation, which was inhibited by intracisternal administration of 10Panx, an inhibitory peptide for pannexin 1 (PANX1) channels. Immunohistochemical analyses revealed that the expression of PANX1 was upregulated in the trigeminal spinal subnucleus caudalis (Vc) following SCC inoculation. The majority of PANX1 immunofluorescence was merged with ionized calcium-binding adapter molecule 1 (Iba1) fluorescence and a part of it was merged with glial fibrillary acidic protein (GFAP) fluorescence. Spike frequencies of Vc nociceptive neurons to noxious mechanical stimulation were significantly enhanced in SCC-inoculated rats, which was suppressed by intracisternal 10Panx administration. Phosphorylated extracellular signal-regulated kinase (pERK)-immunoreactive (IR) neurons increased significantly in the Vc after SCC inoculation, which was inhibited by intracisternal 10Panx administration. SCC inoculation-induced MHWT reduction and increased pERK-IR Vc neuron numbers were inhibited by P2X7 purinoceptor (P2X7R) antagonism. Conversely, these effects were observed in the presence of P2X7R agonist in SCC-inoculated rats with PANX1 inhibition. SCC inoculation-induced MHWT reduction was significantly recovered by intracisternal interleukin-1 receptor antagonist administration. These observations suggest that SCC inoculation causes PANX1 upregulation in Vc microglia and adenosine triphosphate released through PANX1 sensitizes nociceptive neurons in the Vc, resulting in tongue cancer pain.