Low‐Molecular‐Weight CXCR4 Ligands with Variable Spacers

Low‐molecular‐weight CXCR4 ligands based on known lead compounds including the 14‐mer peptide T140, the cyclic pentapeptide FC131, peptide mimetics, and dipicolylamine‐containing compounds were designed and synthesized. Three types of aromatic spacers, 1,4‐phenylenedimethanamine, naphthalene‐2,6‐diyldimethanamine, and [1,1′‐biphenyl]‐4,4′‐diyldimethanamine, were used to build four pharmacophore groups. As pharmacophore groups, 2‐pyridylmethyl and 1‐naphthylmethyl are present in all of the compounds, and several aromatic groups and a cationic group from 1‐propylguanidine and 1,1,3,3‐tetramethyl‐2‐propylguanidine were also used. Several compounds showed significant CXCR4 binding affinity, and zinc(II) complexation of bis(pyridin‐2‐ylmethyl)amine moieties resulted in a remarkable increase in CXCR4 binding affinity.     

A new cascade-less engine operated from subsonic to hypersonic conditions: designed by computational fluid dynamics of compressible turbulence with chemical reactions

By using our computational fluid dynamic models, a new type of single engine capable of operating over a wide range of Mach numbers from subsonic to hypersonic regimes is proposed for airplanes, whereas traditional piston engines, turbojet engines, and scram engines work only under a narrower range of operating conditions. The new engine has no compressors or turbines such as those used in conventional turbojet engines. An important point is its system of super multijets that collide to compress gas for the transonic regime. Computational fluid dynamics is applied to clarify the potential of this engine. The peak pressure at the combustion center is over 2.5 MPa, while that just before ignition is over 1.0 MPa. The maximum power of this engine will be sufficient for actual use. Under the conditions of higher Mach numbers, the main intake passage located in front of the super multijet nozzles, takes in air more. That results in a ram or scramjet engine for supersonic and hypersonic conditions.     

Fullerene lipids: Synthesis of dialkyl 1,2-[6,6]-methano-[60]-fullerene dicarboxylate derivatives

Reaction of C₆₀ fullerene with dialkyl bromomalonate (where the alkyl groups consist of short-, medium-, and long-saturated chains or unsaturated long chains) in the presence of sodium hydride gives [6,6]-bridged mono-adducts of methanofullerene. The spectroscopic properties of such fullerenoid lipids are reported.     

Temperature programmed desorption study of adsorbed species formed by the decomposition of N2O on ion-exchanged copper zeolite catalysts

The nature of the adsorbed species on Cu-ZSM-5 (Cu-Z), Cu-Mordenite (Cu-M), and Cu-Y-zeolite (Cu-Y) was investigated by means of temperature programmed desorption (TPD). When dinitrogen monoxide (N₂O) came into contact with Cu-zeolites above 573 K, the decomposition of N₂O occurred accompanied by the formation of adsorbed oxygen species and adsorbed nitrogen oxide species. In the TPD runs, three O₂ desorption peaks appeared at temperatures of 623, 673, and 753 K and were named -, β-, and γ-peaks, respectively. The O₂ desorption at the - and γ-peaks became quickly saturated after contacting N₂O at 598 K, while the amount of O₂ desorbed at the β-peak increased with time, not reaching a constant level until 120 min of exposure. The activity for the decomposition of N₂O decreased with the accumulation of β-oxygen over the catalyst. The rate of N₂O decomposition depended upon the nature and amount of the copper zeolite catalysts available, as determined by the formation of - and/or β-oxygen.     

Thermomechanical characterization of thermoplastic polyimides to improve the chain collaboration via ureidopyrimidone endcaps

In this report, we explored the effect of incorporating ureidopyrimidone (UPy) linkers in a series of polyimides (PIs) previously studied in our laboratory. The polymers consist of an aromatic diamine monomer with a methylene linker, 4,4′’‐methylenebis (2,6‐dimethylaniline), used to make a robust main chain along with aliphatic polyetherdiamine backbone linkers to decrease rigidity. The polymers were designed to exhibit thermal properties in between those of conventional aromatic PIs and polymers with wholly aliphatic ether diamine links, with an aim to improve the mechanical characteristics. Through dynamic mechanical analysis and differential scanning calorimetry, it is shown that the UPy linkers with their four‐hydrogen bond sites are introduced to connect the chains in series. The connection strengthens the chain interactions and increases the range of the thermal and mechanical properties of the PI. Furthermore, the connecting regions are an important component to preserve the thermal stability of PIs while maintaining the processability. The polymers were characterized by FTIR, nuclear magnetic resonance, GPC, thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, microhardness, and tensile testing. POLYM. ENG. SCI., 59:2231–2246, 2019. © 2019 Society of Plastics Engineers     

Evaluation of precipitates used in strainer head loss testing: Part III. Long-term aluminum hydroxide precipitation tests in borated water

Long-term aluminum (Al) hydroxide precipitation tests were conducted in slightly alkaline solutions containing 2500 ppm boron. The solution temperature was cycled to obtain a temperature history more representative of emergency core cooling system temperatures after a loss-of-coolant accident. The observed Al precipitation boundary was close to predicted results for amorphous precipitates, which are higher than the solubility expected for crystalline forms. Bench-scale and loop head loss test results under various conditions were successfully combined into single map in a temperature - ‘pH + p[Al]_T’ domain, which yielded two bounding lines for Al hydroxide solubility in borated alkaline water that depend on whether or not loop head loss tests with Al alloy coupons are included. Precipitates were observed to form either as fine, cloudy suspensions, which showed very little tendency to settle, or as flocculated precipitates. The flocculation tendency of the precipitates can be qualitatively explained by a colloid stability theory or a phase diagram for protein solutions.