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Atg8 is a unique ubiquitin-like protein that is covalently conjugated with a phosphatidylethanolamine through reactions similar to ubiquitination and plays essential roles in autophagy. Atg7 is the E1 enzyme for Atg8, and it activates the C-terminal Gly116 of Atg8 using ATP. Here, we report the crystal structure of Atg8 bound to the C-terminal domain of Atg7 in an unprecedented mode. Atg8 neither contacts with the central β-sheet nor binds to the catalytic site of Atg7, both of which were observed in previously reported Atg7-Atg8 structures. Instead, Atg8 binds to the C-terminal α-helix and crossover loop, thereby changing the autoinhibited conformation of the crossover loop observed in the free Atg7 structure into a short helix and a disordered loop. Mutational analyses suggested that this interaction mode is important for the activation reaction. We propose that Atg7 recognizes Atg8 through multiple steps, which would be necessary to induce a conformational change in Atg7 that is optimal for the activation reaction.

N-Acetylmannosamine kinase (EC 2.7.1.60) is involved in the catabolism of sialic acid for many bacterial pathogens implicated in human disease such asEscherichia coli,Staphylococcus aureus,Vibrio choleraeandV. vulnificus. Interestingly, some human commensals and bacterial pathogens can scavenge sialic acids from their surrounding environment and degrade them as a source of carbon, nitrogen and energy. This process requires a cluster of genes known as the `Nan-Nag cluster', which have proven to be essential forS. aureusgrowth on sialic acids, suggesting that the pathway is a viable antimicrobial drug target. The enzymeN-acetylmannosamine kinase is involved in the catabolism of sialic acid, transferring a phosphate group from adenosine-5′-triphosphate to the C6 position ofN-acetylmannosamine to generateN-acetylmannosamine-6-phosphate. The gene was cloned into an appropriate expression vector; recombinant protein was expressed inE. coliBL21 (DE3) cells and purifiedviaanion-exchange chromatography, hydrophobic interaction chromatography and size-exclusion chromatography. PurifiedN-acetylmannosamine kinase was screened for crystallization. The best crystal diffracted to a resolution of beyond 2.6 Å in space groupP2. Understanding the structural nature of this enzyme from methicillin-resistantS. aureuswill provide insights necessary for the development of future antimicrobials.

Active pharmaceutical ingredients are composed of single-component or multicomponent crystals. Multicomponent crystals include salts, co-crystals, and solvates. Indinavir sulfate is the ethanol solvate form of indinavir that is known to deliquesce through moisture absorption. However, the detailed behavior of solvent molecules in the crystal has not been investigated. In this study, we studied the desolvation mechanism of indinavir sulfate ethanol and investigated the behavior of solvent molecules in the solid from. Indinavir sulfate ethanol contained 1.7 molecules of ethanol, 0.7 of which desolvated at room temperature. They were originally two ethanol solvent molecules; one molecule of ethanol desolvated at room temperature, and the conformation of the remaining ethanol and t-butyl groups changed in conjunction with the removal of one ethanol molecule. Desolvation could hardly be detected by powder X-ray diffraction; however, it was detected using terahertz spectroscopy. Terahertz measurement of desolvation showed a high correlation with thermogravimetry data, suggesting that desolvation could be observed non-destructively using terahertz spectroscopy. We concluded that indinavir sulfate 1 ethanol deliquesced at 60% relative humidity, and it turned into an amorphous solid after drying.

The diameter selective photoluminescence quenching of single-walled carbon nanotubes (SWCNTs) is observed upon ferrocene encapsulation, which can be attributed to electron transfer from the encapsulated ferrocenes to the SWCNTs. Interestingly, the dependence of the electron transfer process on the nanotube diameter is governed by the molecular orientation of the ferrocenes in the SWCNT rather than the reduction potentials of the SWCNT.

The enzyme N-acetylneuraminate lyase (EC 4.1.3.3) is involved in the metabolism of sialic acids. Specifically, the enzyme catalyzes the retro-aldol cleavage of N-acetylneuraminic acid to form N-acetyl-D-mannosamine and pyruvate. Sialic acids comprise a large family of nine-carbon amino sugars, all of which are derived from the parent compound N-acetylneuraminic acid. In recent years, N-acetylneuraminate lyase has received considerable attention from both mechanistic and structural viewpoints and has been recognized as a potential antimicrobial drug target. The N-acetylneuraminate lyase gene was cloned from methicillin-resistant Staphylococcus aureus genomic DNA, and recombinant protein was expressed and purified from Escherichia coli BL21 (DE3). The enzyme crystallized in a number of crystal forms, predominantly from PEG precipitants, with the best crystal diffracting to beyond 1.70 Å resolution in space group P2₁. Molecular replacement indicates the presence of eight monomers per asymmetric unit. Understanding the structural biology of N-acetylneuraminate lyase in pathogenic bacteria, such as methicillin-resistant S. aureus, will provide insights for the development of future antimicrobials.

Calpain 7, a mammalian ortholog of yeast Cpl1/Rim13 and fungal PalB, is an atypical calpain that lacks a penta-EF-hand domain. Previously, we reported that a region containing a tandem repeat of microtubule-interacting and transport (MIT) domains in calpain 7 interacts with a subset of endosomal sorting complex required for transport (ESCRT)-III-related proteins, suggesting involvement of calpain 7 in the ESCRT system. Although yeast and fungal calpains are thought to be involved in alkaline adaptation via limited proteolysis of specific transcription factors, proteolytic activity of calpain 7 has not been demonstrated yet. In this study, we investigated the interaction between calpain 7 and a newly reported ESCRT-III family member, increased sodium tolerance-1 (IST1), which possesses two different types of MIT-interacting motifs (MIM1 and MIM2). We found that glutathione-S-transferase (GST)-fused tandem MIT domains of calpain 7 (calpain 7MIT) pulled down FLAG-tagged IST1 expressed in HEK293T cells. Coimmunoprecipitation assays with various deletion or point mutants of epitope-tagged calpain 7 and IST1 revealed that both repetitive MIT domains and MIMs are required for efficient interaction. Direct MIT-MIM binding was confirmed by a pulldown experiment with GST-fused IST1 MIM and purified recombinant calpain 7MIT. Furthermore, we found that the GST-MIM protein enhances the autolysis of purified Strep-tagged monomeric green fluorescent protein (mGFP)-fused calpain 7 (mGFP-calpain 7-Strep). The autolysis was almost completely abolished by 10 mmN-ethylmaleimide but only partially inhibited by 1 mm leupeptin or E-64. The putative catalytic Cys290-substituted mutant (mGFP-calpain 7(C290S)-Strep) showed no autolytic activity. These results demonstrate for the first time that human calpain 7 is proteolytically active, and imply that calpain 7 is activated in the ESCRT system.

Gapless Metal (Zinc) Oxide Surge Arresters for a.c. systems contribute to the insulation co-ordination based on the suppression of lightning surges and switching surges. These gapless metal oxide surge arresters using ZnO elements are effective to HVDC systems. This paper describes basic characteristics of ZnO (zinc oxide) elements for d.c. systems and applications of gapless surge arresters to HVDC 125kV frequency converters, HVDC 250kV, upgrade HVDC 500kV converter stations, and HVDC 500kV cables of Japan through the experience of developments and applications of gapless metal oxide surge arresters.

Pure iron and Fe-0.6mass%P alloy were sintered at various temperatures from 1273K to 1623K. Magnetic properties, i,e., magnetic induction at 800 A/m (B8), maximum permeability (μm) and coresive force (Hc) of these alloys were measured using Cioffi type fluxmeter. Then the microstructures of those alloys were investigated using an optical microscope and an EMPA. Sintered density and the magnetic properties of the pure iron are almost constant in the sintering temperature range.On the contrary, those of Fe-0.6mass%P are improved highly with elevating sintering temperature and shows B8=1.35T, μm=8mH/m and Hc=96AT/m at the sintering temperature 1623K. In the Fe-0.6mass%P sintered alloy, P atoms diffuse into the pure iron with an increase in sintering temperature, resulting in forming of the α phase. This densificates the alloy by α phase sintering and then changes pore shape from irregular to spherical. The magnetic properties of Fe-0.6mass%P sintered alloy are improved by mainly densification with spheroidization of the pores.

β-Lactoglobulin (βlg) is the most abundant whey protein in the milks of ruminant animals. While bovine βlg has been subjected to a vast array of studies, little is known about the caprine ortholog. We present an ultra-high resolution crystal structure of caprine βlg complemented by analytical ultracentrifugation and small-angle X-ray scattering data. In both solution and crystalline states caprine βlg is dimeric (KD

The emission properties of cyclic carbazole oligomers are described. The photoluminescent spectra of these cyclic oligomers excited by 350 nm as an excitation wavelength in chloroform have been measured. We found that the emission properties of o-xylene-derived cyclic dimer were different from those of p- and/or m-xylene-derived cyclic dimers although they have the similar molar absorption coefficients and structures. The electroluminescent properties are also described.

We studied the ionization equilibria of the COOH groups bound to the copolymer and to the cross-linked copolymer network (i.e., gel) consisting ofN-isopropylacrylamide (NIPA) and acrylic acid (AAc) by means of potentiometric titration with NaOH. Microgel particles (average hydrodynamic diameter ∼ 120 nm in the acid form and at 25 °C; COOH content ∼ 30 mol %) were employed, in addition to the usual bulk gel (ofa fine grind) with the same COOH content. The microgel was prepared by aqueous redox polymerization usingN,N'-methylenebis(acrylamide) as a cross-linker and sodium dodecylbenzenesulfonate as a surfactant. The titration was carried out at 25 and 35 °C in the absence and the presence of NaCl. The dependence of the apparent dissociation constant (pK a ) on the degree of dissociation (ad) was investigated. It was found that, on the whole, pK a increased with increasing α d but decreased by addition of NaCl. Over a wide α d range there was little difference in pK a between both gels, as well as between the gel and copolymer. At 35 °C and at α d < 0.15, however, an increase in α d brought about a distinct fall in pK a for the microgel as well as the copolymer. At α d < 0.15, pK a was larger at 35 °C than at 25 °C. To discuss these results in connection with the swelling behavior of the gel, size changes of the microgel particles were studied using the photon correlation spectroscopy. The size of the microgel increased with increasing the degree of neutralization (α n ) but decreased by screening the COO - charges with counterions. Over the α n range of 0.6 to 1.0, there was little or no increase in the particle size. These aspects were analogous to those generally observed in the chain expansion of poly(AAc) in solutions, suggesting that the counterion binding effect plays an important role in the swelling of NIPA/AAc gels at high charge densities. It was also suggestive that hydrogen bonding as well as hydrophobic interaction affects the ionization of COOH and thereby the swelling degree at 35 °C and at α d < 0.15. Therefore, it may be concluded that our ionic NIPA gels swell through an increase in the net charge density due to the COO - ions rather than a rise in the osmotic pressure arising from mobile counterions within the gel phase.

Aqueous redox polymerization using a surfactant was studied to prepare submicrometer-sized polyelectrolyte gel particles from a monomer solution containing N-isopropylacrylamide (NIPA), N,N‘-methylenebisacrylamide (Bis), and acrylic acid (AAc) or 1-vinylimidazole (VI). Sodium dodecylbenzenesulfonate and ammonium persulfate were used as the surfactant and the initiator, respectively. The gel particles purified via dialysis were characterized by photon correlation spectroscopy. Since the AAc and VI contents of the monomer solutions were controllable within 0−30 mol %, the diameter of the gel particles with 30 mol % of AAc or VI increased from 125 to 600 nm at 25 °C when converting the carboxyl or imidazolyl groups into the corresponding salt form. However, a complete elimination of charges from the anionic or cationic gel particles gave rise to a neutral gel, the size of which varied from 125 nm at 25 °C (swollen state) to 50 nm at temperatures >35 °C (fully collapsed state). These swelling behaviors were t...

An innovative combined desulphurization/denitration (DeSOx/DeNOx) process was tested in this study. It utilizes the so-called powder-particle fluidized bed (PPFB) to co-fluidize continuously supplied fine DeSOx sorbent (several to tens of micrometers) and coarse DeNOx catalyst (several hundreds of micrometers), the fluidization medium particles. Ammonia for NOx reduction is fed to the system from the bottom of the bed. Thus, SOx and NOx are removed simultaneously from flue gas, used as fluidizing gas, in a single reactor. By using model gases containing SO2 and NO, the removal efficiency of this process was examined in a laboratory PPFB reactor with respect to choices of DeSOx sorbents and DeNOx catalysts, reaction temperature, and major gas components. At a reaction temperature of 623 K and a static height of the catalyst bed of 0.1 m, removals greater than 90% for SO2 and about 80% for NO were achieved with the sorbent CuO·V2O5·K2SO4/Al2O3 (at Cu/S = 1) and the catalyst V2O5·WO3/TiO2 or WO3/TiO2 (at NH3/NO = 1) for a simulated flue gas SO2-NO-H2O-N2-air consisting of oxygen 2vol.%, water vapour 0–10vol.%, SO2 500 ppm and NO 500 ppm. These removals are expected to be further improved by avoiding poisoning by such a copper oxide sorbent on NOx reduction. The possible industrial application of this process is also discussed.

The binding of sodium dodecylbenzene sulfonate (NaDBS) to bulk- and microgels of N -isopropylacrylamide (NIPA) was studied using wet and dry samples. The surfactant uptake by the dry gel sets in as soon as immersed in the surfactant solution, causing the scattering of surfactant molecules all over the gel phase. This makes it possible for the surfactant molecules to bind to the polymer network throughout the gel phase. In the wet gel, however, the surfactant binding begins at the surface of the gel because it already contains a saturated amount of water as the solvent. Even after a certain amount of surfactant molecules have penetrated into the gel, the binding will continue through its surface. Thus, with respect to the distribution of NaDBS concentration within the gel phase, we may predict a different surfactant-binding behavior between the dry and wet samples, regardless of whether we are dealing with a bulk gel or a microgel. In fact, both the volume phase transition temperature ( T v ) and the volume at temperatures T v for the bulk gel to which surfactant binding took place were higher for the dry than for the wet sample. These characteristics were observed in the microgel system. In the case of the bulk gel system, the spatial distribution of bound NaDBS within the gel phase was directly monitored by microscopic spectroscopy. From these results, we concluded that the NaDBS ions inhomogeneously bind to the polymer networks not only within the bulk NIPA gel, but also within the microgel.

A cyclic carbazole oligomer for organic light-emitting diodes is described. This cyclic oligomer has a high glass transition temperature (105°C), and high quality amorphous film can be prepared by the conventional spin-coating technique. We examined the characteristics of this cyclic oligomer for electron transport layer applications. The device structure of indium tin oxide/hole transport layer/electron transport layer/Al was used. The EL device exhibited green light with a luminance of 60 cd m –2 at 15 V and the external quantum efficiency was 0.44%.

A cationic polyelectrolyte gel was prepared by the crosslinking of poly(ethylenimine) (PEI; linear type) with ethylene glycol diglycidyl ether. The swelling characteristic of the PEI gel was investigated as a function of pH, kinds of surfactants, and their concentrations. Four different alkyl sulfate and sulfonates were used: sodium octyl sulfonate (SOS), sodium butyl sulfonate (SBS), sodium dodecyl sulfate (SDS), and sodium dodecylbenzen sulfonate (SDBS). The surfactant binding was also studied through the SDBS uptake by the gel at various concentrations and at pH 3. The following features were observed in the swelling experiments: (a) SDBS, SDS and SOS brought about a discontinuous gel collapse (i.e. volume transition), whereas the gel continuously shrunk with SBS, a behavior which is very close to that with NaCl; (b) the concentration leading to the transition was in the order SDBS

Interpenetrating networks (IPNs) of polyimide (Pl) and epoxy were made by reaction of epoxy (DGEBA) with a polyamic acid (PAA) In addition, epoxy was cured with both a monomeric hardener, pyromellitic dianhydride (PMDA) and PAA to see changes in the morphology and glass transitions caused by the monomeric hardener Due to molecular interlock of the individual polyimide molecules that was brought about by the PAA-epoxy reaction, systems cured with only PAA did not phase separate and showed a significant increase in T g when compared to PMDA cured epoxy. All PMDA cured systems phase separated By dynamic mechanical analysis (DMA). it was confirmed that all systems containing over 20% PAA had two glass transitions. The extent of miscibility of the polyimide into the epoxy was relatively constant PAA cured epoxy systems showed phase miscibility over all compositions and cure regimes.

The effects of sodium dodecyl sulfate (SDS) and sodium dodecylbenzenesulfonate(NaDBS) on the volume phase transition ofN-isopropylacrylamide (NIPA) gels were studied as a function of surfactant concentration and temperature. Both the transition temperature and the swelling ratio increased with increasing surfactant concentration due to the conversion of a nonionic into an ionic NIPA gel through the binding of SDS and NaDBS. This was qualitatively supported by the fact that an increase in the concentration of SDS or NaDBS facilitated the surfactant uptake by the gel. However, little difference was observed in the concentration dependence of the transition temperature between SDS and NaDBS, while SDS exhibited a stronger effect than NaDBS on the concentration changes of the swelling ratio and surfactant uptake. In order to elucidate this aspect, kinetic studies ofNaDBS uptake were performed using cylindrical gels with different diameters. We employed a dry gel free of water, in addition to the usual wet gel, because the dry gel is expected to immediately absorb the solution and to scatter the solute molecules all over the gel phase. An increase in the diameter (therefore, the available surface area) of the wet gels was found to facilitate the surfactant uptake over an experimental period, when its amount was expressed in moles per unit dry mass. However, such a size dependence was negligibly small in the dry gel. These results were interpreted by assuming that the surfactant molecules bind only to the polymer networks located near the gel surface but not to all the networks within the gel. Such an inhomogeneous local binding of surfactant was demonstrated by determining the distribution of NaDBS within thin disks of the surfactant-bound gels using microscopic spectroscopy.

New bridged tetrathiafulvalene derivatives have been synthesized from ethylenedithiotetrathiafulvalene (EDT-TTF) in moderate to good yields using the lithiation-alkylation procedure. The X-ray analysis of the bridged molecule shows a spider-like structure.

Performance of a new copper-based sorbent (CuO•V2O5•K2SO4/Al2O3), for simultaneous removal of SO2 and NO in a powder-particle fluidized bed reactor, was investigated in temperatures ranging from 573 to 873K. The powder-particle fluidized bed was made of a stainless steel tube of 0.053m internal diameter and 1.0m in height above the distributor. In the powder-particle fluidized bed reactor, SO2 was removed by fine sorbents while NO was reduced to N2 with NH3, using coarse DeNOx catalysts (WO3/TiO2 and V2O5•O3/TiO2). The performance of the new sorbent for simultaneous removal of SO2 and NO was compared with that of CuO and CuO•V2O5/Al2O3 sorbents used in authors' previous studies. The new sorbent with the addition of potassium sulfate showed superior reactivity for removal of SO2, but inferior activity for catalytic reduction of NO, compared with CuO and CuO•V2O5/Al2O3 sorbents. Simultaneous removal of over 90% of both sulfur dioxide and nitrogen oxide, however, was achieved using CuO•V2O5•K2SO4/Al2O3 sorbent and WO3/TiO2 catalyst.

Several kinds of SO2 sorbents or catalysts have been evaluated in a process for simultaneous removal of SO2 and NO from flue gas using a powder-particle fluidized bed. In the process, SO2 was captured by fine sorbents and NO was reduced with NH3 catalyzed by a coarse DeNOx catalyst or by both coarse and fine catalysts. Experiments were carried out in a laboratory scale powder-particle fluidized bed reactor of 1.0m in length above the distributor, 0.053m inside diameter, in a temperature range from 373 to 873K. Several kinds of fine sorbents including sodium aluminate, manganese oxide, copper oxide, sodium bicarbonate, and copper oxide supported on alumina with addition of vanadium oxide (CuO•V2O5/Al2O3) were tested in this study. The coarse particles of inactive silica sand and active DeNOx catalysts of WO3/TiO2 and V2O5•WO3/TiO2 were used as fluidized medium particles. The SO2 and NO removal efficiencies by using fine sorbents and coarse catalysts were investigated under the following conditions: static bed height of 0.3m, superficial gas velocity of 0.5m/s, and inlet concentrations of SO2 and NO of 500ppm. Experimental results suggested that CuO•V2O5/Al2O3, sodium aluminate, and sodium bicarbonate were suitable as SO2 sorbents. In a typical temperature range (573-673K) of flue gas, the SO2 removal achieved was 60-70% for CuO•V2O5/Al2O3 at Cu/S mole ratio of 1, about 55% and 40-65% at Na/S mole ratio of 3 for sodium aluminate and sodium bicarbonate. The NO removal approached nearly to 100% at NH3/NO mole ratio of 1 in the active temperature range of the DeNOx catalyst.

Experiments for simultaneous removals of SO2 and NO were conducted in a laboratory-scale powder-particle Fluidized bed reactor of 0.053m inside diameter and 1.0m in length above the distributor in a temperature range of 573-873K. Fine powders, sorbent of SO2, are continuously fed to the fluidized bed, in which coarse fluidized medium particles are fluidized. Iron oxide dust, a by-product of steel mills which contains considerable amounts of iron oxides, was used as sorbent of SO2 to find a cheap sorbent for removal of SOx. Two kinds of coarse particles of inactive silica sand and active WO3/TiO2 catalyst for removal of NOx were used as particles for fluidized medium. Influences of various operating parameters, including reaction temperature, mole ratio of Fe/S, superficial gas velocity, static height of bed, concentration of SO2 at inlet, concentration of NH3 at inlet and kinds of particles for fluidized medium on removal of SO2 were investigated. Furthermore, the effects of reaction temperature, concentration of NH3 at inlet and kinds of particles for fluidized medium on removal of NO were also studied. Experimental results indicated that the iron oxide dust showed potential capacity as low-cost sorbent of SO2 and weak catalytic activity for reduction of NO. A removal of SO2 of 60% was achieved at temperature of 773K and mole ratio of Fe/S of 3, while a nearly 100% removal of NO was attained when NH3/NO was equal to 1, with the use of catalyst for removal of NOx as particle for fluidized medium.

Polyimide-silica hybrid materials were prepared via a modified sol-gel, high pressure-thermal polymerization procedure. Precursor monomer salts were made from ethanol soluble 2,5-diethoxycarboxyl terephthalic acid (p-PME) and either a disiloxanediamine, an aliphatic diamine (1,9 diaminononane) or combinations of the two. Solutions of tetramethoxysilane (TMOS) and monomer salt were transformed into a gel, dehydrated, and the resulting powders were subjected to high pressure and thermal polymerization and transformed into a polyimide-silica composite. By varying the TMOS content, and/or the siloxane to aliphatic diamine ratio, composites of 0 to 100 wt% SiO{sub 2} were made. The silica morphology changed significantly with siloxane/aliphatic PI ratio. Reaction mechanisms, thermal and physical properties and composite morphologies are discussed.

ALG-2 (a gene product of PDCD6) is a 22-kD protein containing five serially repetitive EF-hand structures and belongs to the penta-EF-hand (PEF) family, including the subunits of typical calpains. ALG-2 is the most conserved protein among the PEF family members and its homologs are widely found in eukaryotes. X-ray crystal structures of various PEF proteins including ALG-2 have common features: presence of eight α-helices and dimer formation via paired EF5s that are positioned in anti-parallel orientation. ALG-2 forms a homodimer and a heterodimer with its closest paralog peflin. Like calmodulin, a well-known four-EF-hand protein, ALG-2 interacts with various proteins in a Ca(2+)-dependent fashion, but the binding motifs are completely different. With some exceptions, ALG-2-interacting proteins commonly contain Pro-rich regions, and ALG-2 recognizes at least two distinct Pro-containing motifs: PPYP(X)nYP (X, variable; n=4 in ALIX and PLSCR3) and PXPGF (represented by Sec31A). A shorter alternatively spliced isoform, lacking two residues and designated ALG-2(ΔGF122), does not bind ALIX but maintains binding capacity to Sec31A. X-ray crystal structural analyses have revealed that binding of calcium ions induces the configuration of the side chain of R125 so that it opens Pocket 1, which accepts PPYP, but Pocket 1 remains closed in the case of ALG-2(ΔGF122). ALG-2 dimer has two ligand-binding sites, each in a monomer molecule, and appears to function as a Ca(2+)-dependent adaptor protein to either stabilize a preformed complex or to bridge two proteins on scaffolds in systems of the endosomal sorting complex required for transport (ESCRT) and ER-to-Golgi transport.

New bridged tetrathiafulvalene derivatives have been synthesized from ethylenedithiotetra-thiafulvalene in moderate to good yields using a one-pot procedure. The X-ray analysis of the bridged molecule shows a spider-like structure.

Chlorination, bromination and iodination of bis(methylthio)tetrathiafulvalene (BMT-TTF) produced mainly the dihalogenated products (BMT-TTFX2) with small amounts of the monohalogenated derivatives (BMT-TTFX). The molecular structures of BMT-TTFBr2 and BMT-TTFBr2•I3 have been determined, and the conductivities of CT-complexes and radical salts derived from BMT-TTFX2 have been measured.

A novel cyclic carbazole oligomer, which contains the EL chromophore in the main-chain, for organic light-emitting diodes is described. The device structure of glass substrate/indium tin oxide/hole transport layer/cyclic oligomer (electron transport layer)/Al was employed. The EL device exhibited green light with a luminance of 60 cd/m2 at 15 V.

We report the optical and electroluminescent properties of the organometallic complex lithium tetra-(8-hydroxy-quinolinato) boron (LiBq4). The complex was prepared by the reaction of lithium borohydride with 8-hydroxyquinoline and shows absorption cutoff wavelength of 410 nm and bright blue photoluminescence with a peak wavelength at 466 nm. The ionization potential of LiBq4 was determined to be ∼5.6 eV by a photoemission apparatus. Electroluminescence (EL) properties of three-layer light-emitting diodes (LED) of ITO/PVK:TPD/LiBq4/Alq3/Mg with LiBq4 as the active layer were characterized. The EL spectra of the three-layer device are similar to the PL spectrum of the single layer LiBq4 but with peak wavelength at 475 nm. The results indicate that boron complexes are potential blue emitters for LED applications.

We report a series of polymers with linear, macrocyclic and hyperbranched structures for electroluminescent (EL) applications. The polymers are polycarbazoles (PC) containing different substituents. The polymers are amorphous and are soluble in common organic solvents such as chloroform, and tetrahydrofuran (THF). High optical quality films were obtained by spin-coating from the polymer solutions of chloroform or THF. All these polymers show strong photoluminescence under a UV-lamp illumination. Single and bilayer EL devices consisting of anode/hole transfer layer/electron transfer layer/cathode have been fabricated and characterized. The effects of polymer structures on the energy levels and EL properties are discussed. The results indicated that macrocyclic oligomers and hyperbranched polymers are new candidates for EL devices.

We report the synthesis and characterization of a soluble metal complex polymer for electroluminescent (EL) applications. The polymer was prepared by the reaction of a zinc Schiff base with 4,4′-diphenylmethane-diisocyanate. The polymer is amorphous and with glass transition temperature of 156 °C and is soluble in common organic solvents such as chloroform, tetrahydrofuran (THF), and N-methylpyrrolidinone (NMP). High optical quality films were obtained by spin-coating the polymer solution of THF. The zinc Schiff base, and the polyurethane (PU) shows strong photoluminescence under a UV-lamp illumination. Single and double layer EL devices consisting ITO/hole transfer layer (HTL)/PU/Al have been fabricated and characterized. The results indicated that the complex polymer could act as both electron transport and emissive layers for EL devices.

Verrucomicrobium spinosum is a Gram-negative bacterium that is related to bacteria from the genus Chlamydia. The bacterium is pathogenic towards Drosophila melanogaster and Caenorhabditis elegans, using a type III secretion system to facilitate pathogenicity. V. spinosum employs the recently discovered l,l-diaminopimelate aminotransferase biosynthetic pathway to generate the bacterial cell wall and protein precursors diaminopimelate and lysine. A survey of the V. spinosum genome provides evidence that the bacterium should be able to synthesize peptidoglycan de novo, since all of the necessary genes are present. The enzyme UDP-N-acetylmuramoyl-l-alanyl-d-glutamate: meso-2,6-diaminopimelate ligase (MurE) (E.C. 6.3.2.15) catalyzes a reaction in the cytoplasmic step of peptidoglycan biosynthesis by adding the third amino acid residue to the peptide stem. The murE ortholog from V. spinosum (murE Vs) was cloned and was shown to possess UDP-MurNAc-l-Ala-d-Glu:meso-2,6-diaminopimelate ligase activity in vivo using functional complementation. In vitro analysis using the purified recombinant enzyme demonstrated that MurEVs has a pH optimum of 9.6 and a magnesium optimum of 30 mM. meso-Diaminopimelate was the preferred substrate with a K m of 17 µM, when compared to other substrates that are structurally related. Sequence alignment and structural analysis using homology modeling suggest that key residues that make up the active site of the enzyme are conserved in MurEVs. Our kinetic analysis and structural model of MurEVs is consistent with other MurE enzymes from Gram-negative bacteria that have been characterized. To verify that V. spinosum incorporates diaminopimelate into its cell wall, we purified peptidoglycan from a V. spinosum culture; analysis revealed the presence of diaminopimelate, consistent with that of a bona fide peptidoglycan from Gram-negative bacteria.

Polyimide-silica hybrid materials were prepared via a modified sol-gel, high pressure-thermal polymerization procedure. Precursor monomer salts were made from ethanol soluble 2,5- diethoxycarboxyl terephthalic acid (p-PME) and either a disiloxanediamine, an aliphatic diamine (1,9 diaminononane) or combinations of the two. Solutions of tetramethoxysilane (TMOS) and monomer salt were transformed into a gel, dehydrated, and the resulting powders were subjected to high pressure and thermal polymerization and transformed into a polyimide-silica composite. By varying the TMOS content, and/or the siloxane to aliphatic diamine ratio., composites of 0 to 100 wt% SiO2 were made. The silica morphology changed significantly with siloxane/aliphatic PI ratio. Reaction mechanisms, thermal and physical properties and composite morphologies are discussed.

A novel cyclic carbazole oligomer, which contains the EL chromophore in the main-chain, for organic light-emitting diodes is described. The device structure of glass substrate/indium tin oxide/hole transport layer/cyclic oligomer (electron transport layer)/Al was employed. The EL device exhibited green light with a luminance of 60 cd/m2 at 15 V.

A novel blue electroluminescent material, tris(2,3-methyl-8-hydroxyquinoline) aluminum complex (Alm23q3) , was synthesized and used to fabricate a double-layer organic electroluminescent (EL) device as an emitting material. A device made of ITO-coated glass/triphenyldiamine derivative (TPD)/Alm23q3/Mg:Ag was fabricated, which emits bright blue light with a maximum luminance of 5390 cd/m2 at 19 V.

l,l-Diaminopimelate aminotransferase (DapL) is an enzyme required for the biosynthesis of meso-diaminopimelate (m-DAP) and l-lysine (Lys) in some bacteria and photosynthetic organisms. m-DAP and Lys are both involved in the synthesis of peptidoglycan (PG) and protein synthesis. DapL is found in specific eubacterial and archaeal lineages, in particular in several groups of pathogenic bacteria such as Leptospira interrogans (LiDapL), the soil/water bacterium Verrucomicrobium spinosum (VsDapL) and the alga Chlamydomonas reinhardtii (CrDapL). Here we present the first comprehensive inhibition study comparing the kinetic activity of DapL orthologs using previously active small molecule inhibitors formerly identified in a screen with the DapL of Arabidopsis thaliana (AtDapL), a flowering plant. Each inhibitor is derived from one of four classes with different central structural moieties: a hydrazide, a rhodanine, a barbiturate, or a thiobarbituate functionality. The results show that all five compounds tested were effective at inhibiting the DapL orthologs. LiDapL and AtDapL showed similar patterns of inhibition across the inhibitor series, whereas the VsDapL and CrDapL inhibition patterns were different from that of LiDapL and AtDapL. CrDapL was found to be insensitive to the hydrazide (IC50 >200μM). VsDapL was found to be the most sensitive to the barbiturate and thiobarbiturate containing inhibitors (IC50 ∼5μM). Taken together, the data shows that the homologs have differing sensitivities to the inhibitors with IC50 values ranging from 4.7 to 250μM. In an attempt to understand the basis for these differences the four enzymes were modeled based on the known structure of AtDapL. Overall, it was found that the enzyme active sites were conserved, although the second shell of residues close to the active site were not. We conclude from this that the altered binding patterns seen in the inhibition studies may be a consequence of the inhibitors forming additional interactions with residues proximal to the active site, or that the inhibitors may not act by binding to the active site. Compounds that are specific for DapL could be potential biocides (antibiotic, herbicide or algaecide) that are nontoxic to animals since animals do not contain the enzymes necessary for PG or Lys synthesis. This study provides important information to expand our current understanding of the structure/activity relationship of DapL and putative inhibitors that are potentially useful for the design and or discovery of novel biocides.

Chlorination, bromination and iodination of bis(methylthio)tetrathiafulvalene (BMT-TTF) produced mainly the dihalogenated products (BMT-TTFX2) with small amounts of the monohalogenated derivatives (BMT-TTFX). The molecular structures of BMT-TTFBr2 and BMT-TTFBr2•I3 have been determined, and the conductivities of CT-complexes and radical salts derived from BMT-TTFX2 have been measured.