Polyphenolic Flavonoid Compound Quercetin Effects in the Treatment of Acute Myeloid Leukemia and Myelodysplastic Syndromes

Flavonoids are ubiquitous groups of polyphenolic compounds present in most natural products and plants. These substances have been shown to have promising chemopreventive and chemotherapeutic properties with multiple target interactions and multiple pathway regulations against various human cancers. Polyphenolic flavonoid compounds can block the initiation or reverse the promotion stage of multistep carcinogenesis. Quercetin is one of the most abundant flavonoids found in fruits and vegetables and has been shown to have multiple properties capable of reducing cell growth in cancer cells. Acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) therapy remains a challenge for hematologists worldwide, and the outcomes for patients with both disorders continue to be poor. This scenario indicates the increasing demand for innovative drugs and rational combinative therapies. Herein, we discuss the multitarget effects of the flavonoid quercetin, a naturally occurring flavonol, on AML and MDS.     

A conceptual design of a high-efficiency rep-rated pulsed power system for KrF laser drivers of inertial fusion energy

A conceptual design of a high efficiency, high repetition-rated (rep-rated) pulsed power system for an electron-beam (e-beam) pumped KrF laser driver for inertial fusion energy (IFE) is presented. The proposed pulsed power circuit incorporates linear induction voltage adders to charge pulse forming lines for the generation of 900 kV, 260 ns e-beamsat several Hz. This rep-rated power system meets the pulsed power requirements of the future IFE drivers that necessitate high amplifier efficiency as well as high laser energy. Received: 3 March 2000 / Published online: 16 June 2000     

Polymerization of ϵ-caprolactone using heterobimetallic lanthanocene complexes

The chiral heterobimetallic complexes Li[Ln(η⁵ : η¹-C₅R₄¹SiMe₂NCH₂CH₂R²)₂] (Ln = Y, Lu; C₅R₄¹ = C₅Me₄, C₅H₄, 3-C₅H₃ t Bu; R² = OMe, NMe₂; Me: methyl; tBu: tert-butyl) have been found to polymerize ϵ-caprolactone to give a polymer of high molecular weight (M̄_n < 20 000) and moderate polydispersity (M̄_w/M̄_n < 2.0). Failure to observe a correlation between monomer/initiator ratio and molecular weight suggests a polymerization mechanism different from a pseudo-anionic mechanism.     

Reactions of polymerization-resistant 1,2-dithiolanes with lithiated oxygen heterocycles

Lithiated furans have been found to cleave the S–S bond of polymerization-resistant 1,2-dithiolanes to give the ring opened products in good yields. In the case of lithiated benzofuran, the excess reagent reacted with the normal product to give a mixture. Lithiated dihydrofuran and dihydropyran gave the corresponding ring-opened products that rearranged to spiro-1,3-dithianes during acidic workup. The reaction was applied to the selective synthesis of substrates for intramolecular Diels-Alder reactions. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:281–287, 1998     

An organic electroluminescent device with a molecularly doped polymer hole transport layer

Electroluminescent(EL) devices have been fabricated using four different polymers with different glass transition temperatures (T_g) dispersed with N,N′-bis-(3-methylphenyl)-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine (TPD) as a hole transport layer and tris(8-hydroxyquinoline) aluminum (Alq₃) as an emitting layer. It was found that the higher the T_g of the polymer, the longer the lifetime of the device. From observations of TPD-doped polymer films with optical microscope and atomic force microscope, dispersing TPD in the polymers was found to suppress the crystallization that causes the roughness of the film surface. It was also observed that the higher the T_g of the host polymers, the more difficult TPD crystallization was. The property of the EL device with polyethersulfone (PES) dispersed with TPD was also investigated. The lifetime of EL device with the TPD doped PES film was improved more than five times at a current density below 10 mA/cm² compared with the device with a conventional TPD hole transport layer. © 1997 John Wiley & Sons, Ltd.     

Aerosol generation and measurement of multi-wall carbon nanotubes

Mass production of some kinds of carbon nanotubes (CNT) is now imminent, but little is known about the risk associated with their exposure. It is important to assess the propensity of the CNT to release particles into air for its risk assessment. In this study, we conducted aerosolization of a multi-walled CNT (MWCNT) to assess several aerosol measuring instruments. A Palas RBG-1000 aerosol generator applied mechanical stress to the MWCNT by a rotating brush at feed rates ranging from 2 to 20 mm/h, which the MWCNT was fed to a two-component fluidized bed. The fluidized bed aerosol generator was used to disperse the MWCNT aerosol once more. We monitored the generated MWCNT aerosol concentrations based on number, area, and mass using a condensation particle counter and nanoparticle surface area monitor. Also we quantified carbon mass in MWCNT aerosol samples by a carbon monitor. The shape of aerosolized MWCNT fibers was observed by a scanning electron microscope (SEM). The MWCNT was well dispersed by our system. We found isolated MWCNT fibers in the aerosols by SEM and the count median lengths of MWCNT fibers were 4–6 μm. The MWCNT was quantified by the carbon monitor with a modified condition based on the NIOSH analytical manual. The MWCNT aerosol concentration (EC mass base) was 4 mg/m³ at 2 mm/h in this study.     

Synthesis of Au–Pd bimetallic nanoparticles under energetic irradiation fields

Bimetallic Au–Pd nanoparticles were synthesized under high-energy irradiation fields (1.17 and 1.33 MeV γ-rays, 9 MeV electrons, and 1.6 GeV C ions) from solutions containing Au³⁺ and Pd²⁺ and cationic surfactant (sodium dodecyl sulfate). Particles synthesized by the irradiation were observed using conventional transmission electron microscope (TEM) and annular dark-field scanning transmission electron microscopy (ADF-STEM). The particles synthesized by γ-rays and C ion irradiation exhibit core–shell structure with a Au-core and a Pd-shell. The dependence of the size distribution of nanoparticles on the dose rate is discussed.     

Titanium complexes with sulfur‐linked bis(phenolate) ligands

High‐quality crystals of two bis(phenolate)titanium complexes, namely dichlorido{4,4′‐dimethyl‐2,2′‐[cyclohexane‐1,2‐diylbis(sulfanediyl)]diphenolato}titanium(IV), [Ti(C₂₀H₂₂O₂S₂)Cl₂], (I), and dichlorido{2,2′‐[cyclohexane‐1,2‐diylbis(sulfanediyl)]diphenolato}titanium(IV), [Ti(C₁₈H₁₈O₂S₂)Cl₂], (II), were obtained by reactive crystallization. Depending on the solvent, compound (II) was obtained as unsolvated (IIa) or as the toluene hemisolvate, [Ti(C₁₈H₁₈O₂S₂)Cl₂]·0.5C₇H₈, (IIb). These systems without bulky substituents on the aromatic phenolate rings serve as ideal model compounds for precatalysts. The excellent X‐ray diffraction data will help clarify the nature of the mismatched interactions between the soft S atoms within the ligand and the hard titanium center. Molecule (I) has crystallographic C₂ symmetry.     

Chromatography in silico, quantitative analysis of retention of aromatic acid derivatives

A quantitative analysis of the retention of aromatic acid derivatives in reversed-phase liquid chromatography (RPLC) is conducted using a molecular mechanics calculation in the CAChe program. The molecular interaction energy value is calculated by subtracting the energy value of the complex from the sum of energy values of a model phase and an analyte. Several model phases are constructed, and the feasibility of applying the method to a variety of compounds is examined based on improving the contact surface area and the capability of computer software and hardware. Interaction energy values are calculated for both molecular and ionic forms. The predicted retention factors of partially ionized acids obtained using a combination of dissociation constants correlated well with the values measured by RPLC with pH-controlled eluents.