Synthesis and Field Tests of Possible Minor Components of the Sex Pheromone of Prionus californicus

Earlier work has shown that adult male Prionus californicus Motschulsky (Coleoptera: Cerambycidae) are attracted to the female-produced compound (3R,5S)-3,5-dimethyldodecanoic acid, and to a synthetic mixture of the four stereoisomers of 3,5-dimethyldodecanoic acid. Here, we report the results of field trials that tested whether or not three structurally related compounds (methyl 3,5-dimethyldodecanoate, 3,5-dimethyltridecanoic acid, and 3,5-dimethylpentadecanoic acid), present in extracts of virgin females, are attractive, and whether or not they influence attraction to 3,5-dimethyldodecanoic acid. In a trial with single components, only traps baited with the acid or its methyl ester captured more beetles than did control traps; catches to the acid were five times higher than to the methyl ester. Another trial, excluding 3,5-dimethyldodecanoic acid, confirmed the activity of the methyl ester. Finally, addition of the three compounds to 3,5-dimethyldodecanoic acid, in the ratio found in extracts from female beetles, gave a catch similar to that of traps baited with 3,5-dimethyldodecanoic acid alone. Consequently, the function of these minor compounds remains undetermined.     

A facile approach to fabricate porous nylon 6 nanofibers using silica nanotemplate

Porous Nylon 6 nanofibers were prepared using silica nanoparticles as the template. Firstly, Nylon 6/silica composite nanofibers were prepared as precursors by electrospinning Nylon 6 solutions containing different contents of silica nanoparticles. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to examine the surface morphology and the inner structure of composite nanofibers; where it was found that silica nanoparticles were distributed both inside and on the surface of nanofibers. Analytical techniques [Fourier transform infrared (FTIR), differential scanning calorimetry, thermal gravimetric analysis (TGA), and wide‐angle X‐ray diffraction) were used to study the structure and properties of these composite nanofibers. The glass transition, melting, and crystallization processes of the fibers were affected by the addition of silica nanoparticles. Secondly, porous Nylon 6 nanofibers were obtained by removing silica nanoparticles via hydrofluoric acid treatment. The removal of silica nanoparticles was confirmed using FTIR and TGA tests. SEM and TEM observations revealed the formation of the porous structure in these nanofibers. After the formation of the porous structure, Brunauer–Emmett–Teller specific surface areas of nanofibers were increased as compared to solid Nylon 6 and composite nanofibers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and structure-activity relationship of the isoindolinyl benzisoxazolpiperidines as potent,selective, and orally active human dopamine D4 receptor antagonists

A new class of potent dopamine D(4) antagonists was discovered with selectivity over dopamine D(2) and the alpha-1 adrenoceptor. The lead compound was discovered by screening our compound collection. The structure-activity relationships of substituted isoindoline rings and the chirality about the hydroxymethyl side chain were explored. The isoindoline analogues showed modest differences in potency and selectivity. The S enantiomer proved to be the more potent enantiomer at the D(4) receptor. Several analogues with greater than 100-fold selectivity for D(4) over D(2) and the alpha-1 adrenoreceptor were discovered. Several selective analogues were active in vivo upon oral or intraperitoneal administration. A chiral synthesis starting from either D- or L-O-benzylserine is also described.     

Effects of a Nd—Fe—B magnetic filler on the crystallization of poly(phenylene sulfide)

The crystallization of poly(phenylene sulfide) (PPS) in a polymer–magnetic Nd—Fe—B powder suspension was studied. Isothermal crystallization behavior was analyzed by way of differential scanning calorimetry, and the kinetics were described via the Avrami equation. The Avrami parameters and the crystallization times were strongly affected by both the particle size and the presence of a coupling agent coated on the filler particles. The small Nd—Fe—B particles exhibited long induction and half‐times, whereas the large particles tended to have short crystallization times. Particles ranging from 38 to 150 μ appeared to have similar crystallization times and to have no significant change in the value of Avrami index with melt crystallization temperature. As a result of these analyses, the dynamic mechanical properties were determined to correlate the fundamental polymer crystallization characteristics and the physical properties of the PPS binder. The enhancement of the wetting of the filler to the binder was promoted through the coupling agent, as confirmed by dynamic mechanical testing performed on the samples. The storage modulus typically decreased because of the presence of the uncoated small particles. Conversely, the loss modulus was enhanced because of the presence of the coated small particles in the PPS binder. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1091–1102, 2002     

Thermal properties of sodium borosilicate glasses as a function of sulfur content

Sulfur trioxide (SO₃) additions, up to 3.0 mass%, were systematically investigated for effects on the physical properties of sodium borosilicate glass melted in air, with a sulfur-free composition of 50SiO₂–10Al₂O₃–12B₂O₃–21Na₂O–7CaO (mass%). Solubility measurements, using electron microscopy chemical analysis, determined the maximum loading to be ~1.2 mass% SO₃. It was found that measured sulfur (here as sulfate) additions up to 1.18 mass% increased the glass transition temperature by 3%, thermal diffusivity by 11%, heat capacity by 10%, and thermal conductivity by 20%, and decreased the mass density by 1%. Structural analysis, performed with Raman spectroscopy, indicated that the borosilicate network polymerized with sulfur additions up to 3.0 mass%, presumably due to Na₂O being required to charge compensate the ionic additions, thus becoming unavailable to form non-bridging oxygen in the silicate network. It is postulated that this increased cross-linking of the borosilicate backbone led to a structure with higher dimensionality and average bond energy. This increased the mean free paths and vibration frequency of the phonons, which resulted in the observed increase in thermal properties.     

5-Benzylidene-4-Oxazolidinones Are Synergistic with Antibiotics for the Treatment of Staphylococcus aureus Biofilms

The failure of frontline antibiotics in the clinic is one of the most serious threats to human health and requires a multitude of novel therapeutics and innovative approaches to treatment so as to curtail the growing crisis. In addition to traditional resistance mechanisms resulting in the lack of efficacy of many antibiotics, most chronic and recurring infections are further made tolerant to antibiotic action by the presence of biofilms. Herein, we report an expanded set of 5-benzylidene-4-oxazolidinones that are able to inhibit the formation of Staphylococcus aureus biofilms, disperse preformed biofilms, and, in combination with common antibiotics, are able to significantly reduce the bacterial load in a robust collagen-matrix model of biofilm infection.     

Immunogenic Cell Death of Breast Cancer Stem Cells Induced by an Endoplasmic Reticulum-Targeting Copper(II) Complex

Immunogenic cell death (ICD) offers a method of stimulating the immune system to attack and remove cancer cells. We report a copper(II) complex containing a Schiff base ligand and a polypyridyl ligand, 4 , capable of inducing ICD in breast cancer stem cells (CSCs). Complex 4 kills both bulk breast cancer cells and breast CSCs at sub-micromolar concentrations. Notably, 4 exhibits greater potency (one order of magnitude) towards breast CSCs than salinomycin (an established breast CSC-potent agent) and cisplatin (a clinically approved anticancer drug). Epithelial spheroid studies show that 4 is able to selectively inhibit breast CSC-enriched HMLER-shEcad spheroid formation and viability over non-tumorigenic breast MCF10 A spheroids. Mechanistic studies show that 4 operates as a Type II ICD inducer. Specifically, 4 readily enters the endoplasmic reticulum (ER) of breast CSCs, elevates intracellular reactive oxygen species (ROS) levels, induces ER stress, evokes damage-associated molecular patterns (DAMPs), and promotes breast CSC phagocytosis by macrophages. As far as we are aware, 4 is the first metal complex to induce ICD in breast CSCs and promote their engulfment by immune cells.     

Glass‐polymer melt hybrids. I: Viscoelastic properties of novel affordable organic‐inorganic polymer hybrids

A novel class of organic‐inorganic polymer hybrids was developed by melt‐blending up to 50 (v/v) % [about 83 (w/w) %] tin‐based polyphosphate glass (Pglass) and low‐density polyethylene (LDPE) in conventional plastics processing equipment. The liquid‐ and solid‐state rheology of the polymer hybrids was studied under oscillatory shear flow and deformation to understand the behavior of these materials and to accelerate efforts to melt process the Pglass with organic polymers. All the materials were found to be linearly viscoelastic in the range of temperature and frequencies examined and their viscoelastic functions increased with increasing Pglass concentration. The Pglass significantly enhanced the shear‐thinning characteristics of the Pglass‐LDPE hybrid, indicating the presence of nonlinear chemical and physical interactions between the hybrid components. Morphological examination of the materials by scanning electron microscopy revealed interesting evolution of microstructure of the Pglass phase from droplets (or round beads) to elongated and interpenetrating network structures as the glass concentration was increased in the Pglass‐LDPE hybrids. Melt viscosities of the materials were well described by a simple power‐law equation and a Maxwellian (Hookean) model with three relaxation times. Time‐temperature superpositioning (TTS) of the complex viscosity versus frequency data was excellent at 170°C < T < 220°C and the temperature dependencies of the shift factors conformed excellently well to predictions from an Arrhenius‐type relation, enabling calculation of the flow‐activation energies (25–285 kj/mol) for the materials. The beneficial function of the Pglass in the hybrid system was significantly enhanced by pre‐treating the glass with coupling agents prior to incorporating them into the Pglass‐LDPE hybrids.     

Inversion domain boundaries in Mn and Al dual‐doped ZnO: Atomic structure and electronic properties

The atomic and electronic structures of inversion domain boundaries in Mn‐Al dual‐doped ZnO (Zn_0.89Mn_0.1Al_0.01O) have been investigated. Using atomic‐resolution scanning transmission electron microscopy, a head‐to‐head c‐axis configuration and cation stacking sequence of αβαβ|γ|αβαβ along the c‐axis were observed at the basal‐plane inversion domain boundary. Energy‐dispersive X‐ray spectroscopy and electron energy‐loss spectroscopy revealed significant localization of Mn and minor localization of Al at the basal‐plane inversion domain boundary. Based on experimental findings, a Mn‐doped basal‐plane inversion domain boundary slab model was constructed and refined by first principles calculations. The model is in agreement with atomic‐resolution images. The local electronic density of states of the slab model basal‐plane inversion domain boundary shows a hybridization of the Mn d and O p states within the valence band and localized Mn d states in the conduction band. The thermoelectric properties of Zn_0.99?xMn_xAl_0.01O ceramics have been reported in a previous work. In this work, the effects of inversion domain boundaries on the thermoelectric properties are discussed. In comparison to Zn_0.99?xMn_xAl_0.01O ceramics with x≤0.05, inversion domain boundaries in Zn_0.89Mn_0.1Al_0.01O caused thermal and electrical conductivity reduction due to interface scattering of phonons and electrons. The Seebeck coefficient increased, suggesting electron filtering at inversion domain boundaries.