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In this paper, a novel structure for a vertical power MOSFET is designed to have higher breakdown voltage and lower specific on-state resistance compared with a conventional vertical power MOSFET.

The innate immune response is the first defence system against pathogenic microorganisms, and cytosolic detection of pathogen-derived DNA is believed to be one of the major mechanisms of interferon production. Recently, the mammalian ER membrane protein STING (stimulator of IFN genes; also known as MITA, ERIS, MPYS and TMEM173) has been found to be the master regulator linking the detection of cytosolic DNA to TANK-binding kinase 1 (TBK1) and its downstream transcription factor IFN regulatory factor 3 (IRF3). In addition, STING itself was soon discovered to be a direct sensor of bacterial cyclic dinucleotides such as c-di-GMP or c-di-AMP. However, structural studies of apo STING and its complexes with these cyclic dinucleotides and with other cognate binding proteins are essential in order to fully understand the roles played by STING in these crucial signalling pathways. In this manuscript, the successful crystallization of the C-terminal domain of murine STING (STING-CTD; residues 138-344) is reported. Native and SeMet-labelled crystals were obtained and diffracted to moderate resolutions of 2.39 and 2.2 Å, respectively. Published version

We have prepared semi-interpenetrating polyacrylate networks (PA/BA-m s-IPNs) through rapid photopolymerization of a triacrylate monomer (TMPTA) in the presence of a photoinitiator (I184), a tetramercaptane transfer agent (4SH), and N-methyl-bisbenzoxazine (BA-m). Next, we prepared novel fully interpenetrating polyacrylate (PA) and polybenzoxazine (PBZ) networks (PA/PBZ f-IPNs) through thermal polymerization of the BA-m monomer at 180 °C for 4 h. For the PA/BA-m s-IPNs, the BA-m monomers can be frozen and dispersed in the UV-cured PA network within 5 min to inhibit macrophase separation. After thermal polymerization, the phenol units of the ring-opened PBZ segments can form a hydrogen-bonding interface with the carbonyl groups to improve the compatibility between the PBZ microdomains and the PA networks. From an analysis using Kissinger's method, the non-isothermal kinetics of the thermal polymerization for the PA/BA-m s-IPNs indicate that an increase in the PA content increased the steric hindrance of PBZ polymerization. We used DSC, TGA, and contact angle analyses to determine the glass transition temperature, thermal stability, and surface free energy, respectively, of the PA/PBZ f-IPNs. The thermal stability and surface free energy of these PA/PBZ f-IPNs display linear relationships with respect to the PBZ content.

Objective Postoperative maxillary mucoceles occur as a delayed complication of radical surgical intervention in the maxillary sinus. Conventionally, the recommended procedure for treating this entity has been the revised Caldwell-Luc operation. In this study, we present a less invasive treatment methodology which is as safe and effective. Materials and Methods Between January 1988 and December 2006, inclusively, 36 patients (47 sides) were enrolled in the study. Twenty-eight patients (38 sides) underwent the endoscopic marsupialization technique. Eight patients (9 sides) received a revised Caldwell-Luc operation, and this group was used as the control. Under nasoendoscopic guidance, an antrostoma was created through the inferior (29/38) or middle (9/38) meatus, and the opening was then enlarged to a diameter almost equal to that of the mucocele itself. A 15° intranasal drill was used where the medial wall of the maxillary sinus was bony. Results Only one patient complained of mild cheek pain after marsupialization surgery. The opening remained patent in 89.5% (34/38) of the mucoceles 1 year after the transnasal endoscopic operation. Twenty of the 38 maxillary sinus mucoceles had a bony wall between the membranous mucocele and the nasal cavity, while the wall was membranous in the remaining 18. Stoma closure was noted in four mucoceles at an average of 4.1 weeks after the operation. A statistically significant tendency for stoma closure was observed for mucoceles with bony walls adjacent to the inferior or middle meatus compared with membranous ones. Conclusion The transnasal approach using a powered instrument has the advantage of decreased postoperative suffering. Based on the results of this study, it appears reasonable to suggest that this is a useful treatment method for a unilocular mucocele adjacent to the medial wall of the antrum.

Unfortunately,theuseoftefloncomeswithcertaindisadvantages,suchasthoseresultingfromits low oil repellence, high cost, and poor processability.Considerable research efforts have therefore been directedtowards the development of nonwettable, low-surface-free-energy polymeric materials that exhibit good film-formingcharacteristics.

We have generated porous polybenzoxazine (PBZZ) materials by using a B-a type PBZZ as the matrix and various molecular weights of poly(e-caprolactone) (pa-PCL) as the labile constituent. The slight degree of hydrogen bonding that exists between the two polymers results in micro-phase separation without an excess degree of aggregation occurring. The porous structures form after hydrolysis of the PCL domains; we characterized them using a variety of techniques, including FT-IR spectroscopy, DSC, TGA, FE-SEM, and DEA. At 298 K and 10 5 Hz, we obtained a thin, transparent, and nanoporous film that has a very low dielectric constant (1.95).

β-Cyclodextrin (β-CD) forms inclusion complexes (ICs) with adamantane-modified benzoxazines (2 benzoxazine and 3 benzoxazine). These benzoxazines can readily penetrate into the CD's hydrophobic cavity, causing turbidity of their solutions, from which fine crystalline powders are obtained. We characterized these complexes by powder X-ray diffraction, 13C and 13C CP/MAS NMR spectroscopies, DSC, and TGA. The X-ray diffraction and solid-state 13C CP/MAS NMR spectroscopy indicate that the IC domains of the polypseudorotaxanes maintain their channel-type structures after the ring-opening curing reactions have occurred. Furthermore, DSC measurements indicate that complexing the adamantane-modified benzoxazine units with β-CDs result in stiffer main chains and, thus, higher glass transition temperature. TGA also indicates that the inclusion complexes have enhanced its thermal stability.

We have successfully synthesized a novel benzoxazine ring-containing polyhedral oligomeric silsesquioxane (BZ-POSS) monomer by two routes: (1) hydrosilylation of a vinyl-terminated benzoxazine using the hydro-silane functional group of a polyhedral oligomeric silsesquioxane (H-POSS) and (2) reaction of a primary amine-containng POSS (Amine-POSS) with phenol and formaldehyde. The benzoxazine-containing POSS (BZ-POSS) monomer can be copolymerized with other benzoxazine monomers through ring-opening polymerization under conditions similar to that used for polymerizing pure benzoxazines. Thermal properties of these POSS-containing organic/inorganic polybenzoxazine nanocomposites have been improved over the pure polybenzoxazine analyzed by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The BZ-POSS monomer is poorly miscible with the benzoxazine monomer and tends to aggregate and forms its own domains, both before and after polymerization. At a higher BZ-POSS content, gross aggregation occurs and results in a lower than expected improvement in the thermal properties.

We have prepared polystyrene/clay nanocomposites using an emulsion polymerization technique. The nanocomposites were exfoliated at up to a 3 wt% content of pristine clay relative to the amount of polystyrene (PS). We used two different surfactants for the montmorillonite: the aminopropylisobutyl polyhedral oligomeric silsesquioxane (POSS) and the ammonium salt of cetylpyridinium chloride (CPC). Both surfactants can intercalate into the layers of the pristine clay dispersed in water prior to polymerization. Although the d spacing of the POSS-intercalated clay is relatively smaller than that of the CPC-intercalated clay, PS more easily intercalates and exfoliates the POSS-treated clay than the CPC-treated clay. IR spectroscopic analysis further confirms the intercalation of POSS within the clay layers. We used X-ray diffraction (XRD) and transmission electron microscopy (TEM) to characterize the structures of the nanocomposites. The nanocomposite prepared from the clay treated with the POSS containing surfactant is exfoliated, while an intercalated clay was obtained from the CPC-treated surfactant. The molecular weights of polystyrene (PS) obtained from the nanocomposite is slightly lower than the virgin PS formed under similar polymerization conditions. The value of Tg of the PS component in the nanocomposite is 8 °C higher than the virgin PS and its thermal decomposition temperature (21 °C) is also higher significantly. The presence of the POSS unit in the MMT enhances the thermal stability of the polystyrene.

The sol–gel process was used to prepare a photosensitive inorganic–organic composite, silica/poly(2-hydroxymethyl methacrylate). Its nanoscale morphology was observed with field emission scanning electron microscopy at high magnifications (e.g., 160,000×). The size of the particles in the nanocomposite synthesized under various preparation conditions fell in the range of 20–50 nm. The effects of the pH, reactant composition, and solvent content in the reaction mixture on the thermal and mechanical properties of the nanocomposite were studied with thermogravimetric analysis, dynamic mechanical analysis, and thermomechanical analysis. The thermal stability of the synthesized nanocomposite could generally be improved by an increase in the molar ratio of the inorganic component, a reduction in the reaction pH, or an increase in the solvent content. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1927–1935, 2004

The structure of benzoxazines is similar to that of phenolic resin through thermal self-curing of the heterocyclic ring opening reaction that neither requires catalyst nor releases any condensation byproduct. These polybenzoxazine resins have several outstanding properties such as high thermal stability and high glass transition temperature. To better understand the curing kinetics of this copolybenzoxazine thermosetting resin, dynamic and isothermal differential scanning calorimetry measurements were performed. Three models, the Kissinger method, the Flynn–Wall–Osawa method, and the Kamal method, were used to describe the curing process. Dynamic kinetic activation energies based on Kissinger and Flynn–Wall–Osawa methods are 72.11 and 84.06 KJ/mol, respectively. The Kamal method based on an autocatalytic model results in a total order of reaction between 2.66 and 3.03, depending on curing temperature. Its activation energy and Arrhenius preexponential are 50.3 KJ/mol and 7959, respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 730–737, 2005

Two novel structures of adamantane-modified benzoxazines were synthesized from 4-(1-adamantyl)-phenol through the incorporation of adamantane as a pendant group into the polybenzoxazine backbone. Both 1H-NMR and Fourier transform infrared spectra were used to characterize these structures. The rigid structure of the adamantane tended to hinder the chain mobility (boat anchor effect) and substantially enhanced the thermal properties, including the glass-transition temperature and decomposition temperature, especially for poly(6-adamantyl-3-methyl-3,4-dihydro-2H-1,3-benzoxazine). In the poly(6-adamantyl-3-phenyl-3,4-dihydro-2H-1,3-benzoxazine) system, however, the opposite result for the glass-transition temperature was observed and it was interpreted as lower crosslinking density. The phenyl group was bulkier than the methyl group, and the movement of the molecular chain was hindered between bridging points during the curing process; this resulted in a lower crosslinking density and a lower glass-transition temperature than those of poly(6-adamantyl-3-methyl-3,4-dihydro-2H-1,3-benzoxazine). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 932–940, 2004

It is well-known that low dielectric materials are used as insulating materials, and the incorporation of fluorinated substitutes into polymer is able to decrease its dielectric constant because of small dipole and the low polarizability of the C–F bond. In this study, a novel structure of the fluorinated benzoxazine (F-1 benzoxazine) has been synthesized by incorporating the trifluoromethyl groups into the monomer, and its structure has also been characterized by 1H NMR, 19F NMR and FT-IR. Further, we have prepared the fluorinated copolybenzoxazine (B-a/F-1=1/1) with substantially reduced dielectric constant at K=2.36. In addition, this fluorinated copolybenzoxazine possesses high glass transition temperature and high thermal stability, which is suitable for high temperature operation for certain special processes of interlayer dielectrics.

The thermal properties and hydrogen bonding behavior of B-a type polybenzoxazine (PBZZ)/PVP blends were investigated by DSC and FTIR. The DSC result shows a single Tg over the entire compositions and a large positive deviation based on Kwei equation was observed in the Tg versus composition diagram, implying that strong hydrogen bonding interaction exists between PBZZ and PVP segments. The strength of hydrogen bonding interaction is in the order of inter-association between the hydroxyl group of PBZZ and the carbonyl group of PVP (K A =594 L mol −1 ) >self-association between the hydroxyl group of pure PBZZ (K B =72.6 L mol −1 ) >inter-association between the hydroxyl and the Mannich-based bridge of pure PBZZ (K C L mol −1 ). Good correlation between DSC and FTIR analysis were observed.

The sol–gel method was employed to prepare an inorganic–organic hybrid, silica/poly(HEMA). The chemical structure of this material was analyzed by means of FTIR and solid 29Si-NMR. Using TEM and low voltage FESEM imaging at high magnifications (e.g., 300 KX), the hybrid was found to comprise nano-particles whose sizes fall largely over the range 20–30 nm.

The mammalian ER protein STING (stimulator of interferon genes; also known as MITA, ERIS, MPYS or TMEM173) is an adaptor protein that links the detection of cytosolic dsDNA to the activation of TANK-binding kinase 1 (TBK1) and its downstream transcription factor interferon regulatory factor 3 (IFN3). Recently, STING itself has been found to be the direct receptor of bacterial c-di-GMP, and crystal structures of several human STING C-terminal domain (STING-CTD) dimers in the apo form or in complex with c-di-GMP have been published. Here, a novel set of structures of mouse STING-CTD (mSTING137-344) in apo and complex forms determined from crystals obtained under different crystallization conditions are reported. These novel closed-form structures exhibited considerable differences from previously reported open-form human STING-CTD structures. The novel mSTING structures feature extensive interactions between the two monomers, a unique asymmetric c-di-GMP molecule with one guanine base in an unusual syn conformation that is well accommodated in the dimeric interface with many direct specific interactions and two unexpected equivalent secondary peripheral c-di-GMP binding sites. Replacement of the amino acids crucial for specific c-di-GMP binding in mSTING significantly changes the ITC titration profiles and reduces the IFN-[beta] reporter luciferase activity. Taken together, these results reveal a more stable c-di-GMP binding mode of STING proteins that could serve as a template for rational drug design to stimulate interferon production by mammalian cells. Published version

Iron is vital to the majority of prokaryotes, with ferrous iron believed to be the preferred form for iron uptake owing to its much better solubility. The major route for bacterial ferrous iron uptake is found to be via an Feo (ferrous iron-transport) system comprising the three proteins FeoA, FeoB and FeoC. Although the structure and function of FeoB have received much attention recently, the roles played by FeoA and FeoC have been little investigated to date. Here, the tertiary structure of FeoA from Stenotrophomonas maltophilia (Sm), a vital opportunistic pathogen in immunodepressed hosts, is reported. The crystal structure of SmFeoA has been determined to a resolution of 1.7 A using an Se single-wavelength anomalous dispersion (Se-SAD) approach. Although SmFeoA bears low sequence identity to eukaryotic proteins, its structure is found to adopt a eukaryotic SH3-domain-like fold. It also bears weak similarity to the C-terminal SH3 domain of bacterial DtxR (diphtheria toxin regulator), with some unique characteristics. Intriguingly, SmFeoA is found to adopt a unique dimer cross-linked by two zinc ions and six anions (chloride ions). Since FeoB has been found to contain a G-protein-like domain with low GTPase activity, FeoA may interact with FeoB through the SH3–G-protein domain interaction to act as a ferrous iron-transport activating factor.

The two structures reported in the article by Chin et al. [(2013). Acta Cryst. D69, 352–366] have been further refined and corrected.