Goniodilactone and gomoheptenolactone,two novel cytotoxic styryllactones from the leaves of Goniothalamus cheliensis

Two novel styryllactones,goniodilactone（1） and gonioheptenolactone（2）,were isolated from the leaves of Goniothalamus cheliensis Hu.Their structures were determined on the basis of spectroscopic data as well as X-ray crystallography analysis. Compounds 1 and 2 exhibited significant cytotoxicities in a panel of human cancer cells,including DU-145,PC-3,MCF-7,A-549, KB and KBvin,with GI₅₀S in the range of 1.29-4.56μg/mL.     

Incompatible reaction evaluation and accident investigation of various acids in chemical industries

This article covers the incompatible properties of nitric acid (HNO₃) with formic acid (CH₂O₂), and more generally with various acids such as sulfuric acid (H₂SO₄), hydrochloric acid (HCl), and acetic acid (C₂H₄O₂). Differential scanning calorimetry (DSC) was employed to determine the thermal hazard such as heat of decomposition (ΔH _d), exothermic onset temperature (T ₀), etc., in various acids. T ₀ of HNO₃ and CH₂O₂ were determined as 50 °C using DSC. Thus it has been observed that HNO₃ mixed with CH₂O₂ should be prohibited during transportation, storage, and use. And more generally, process safety engineers and operator must take care to handle tanker and storage tank of typical acids in the transportation, storage, and manufacturing process. It is clear that there exists a need to follow and enforce in the chemical industries safety data sheets, globally harmonized system of classification and labeling of chemicals of United Nations (UN), education of safety and health, emergency response system, and process safety management. It is the aim of the present study concerning HNO₃ with various acids.     

Ligand‐Functionalization of BPEI‐Coated YVO4:Bi3+,Eu3+ Nanophosphors for Tumor‐Cell‐Targeted Imaging Applications

In this study, surface‐functionalized, branched polyethylenimine (BPEI)‐modified YVO₄:Bi³⁺,Eu³⁺ nanocrystals (NCs) were successfully synthesized by a simple, rapid, solvent‐free hydrothermal method. The BPEI‐coated YVO₄:Bi³⁺,Eu³⁺ NCs with high crystallinity show broad‐band excitation in the λ=250 to 400 nm near‐ultraviolet (NUV) region and exhibit a sharp‐line emission band centered at λ=619 nm under excitation at λ=350 nm. The surface amino groups contributed by the capping agent, BPEI, not only improve the dispersibility and water/buffer stability of the BPEI‐coated YVO₄:Bi³⁺,Eu³⁺ NCs, but also provide a capability for specifically targeted biomolecule conjugation. Folic acid (FA) and epidermal growth factor (EGF) were further attached to the BPEI‐coated YVO₄:Bi³⁺,Eu³⁺ NCs and exhibited effective positioning of fluorescent NCs toward the targeted folate receptor overexpressed in HeLa cells or EGFR overexpressed in A431 cells with low cytotoxicity. These results demonstrate that the ligand‐functionalized, BPEI‐coated YVO₄:Bi³⁺, Eu³⁺ NCs show great potential as a new‐generation biological luminescent bioprobe for bioimaging applications. Moreover, the unique luminescence properties of BPEI‐coated YVO₄:Bi³⁺,Eu³⁺ NCs show potential to combine with a UVA photosensitizing drug to produce both detective and therapeutic effects for human skin cancer therapy.     

Computational Study of the Substitution Effect on the Mechanism for the Gold(I)‐Catalyzed Ring Expansions of Unactivated Alkynylcyclopropanes

The ring expansion reactions of unactivated alkynylcyclopropanes X‐C≡C‐C₃H₅ → X‐C=C₄H₅ (X = H, F, Cl, Me, OMe, NMe₂, CMe₃) were examined using the density functional theory calculations. All of the structures were completely optimized at the B3LYP/6‐311++G** level of theory. For clarify the effect of the cationic gold(I), we also added AuPH₃⁺ as the catalyst into the system and the structures for Au were calculated at the B3LYP/LANL2DZ level of theory. The main finding of this work is that the singlet‐triplet splitting of X‐C≡C‐C₃H₅ play an important role in determining the kinetic and thermodynamic stability of the unactivated ring expansion reactions. When X‐C≡C‐C₃H₅ with a smaller singlet‐triplet splitting is utilized, the reaction has a smaller activation energy and a larger exothermicity.     

Fingerprints of Phalaenopsis Tissues in Growth and Spike Induction Periods—A Solid‐state 13C NMR Approach

Solid‐state Nuclear Magnetic Resonance (ss‐NMR) ¹³C single‐pulse excitation spectroscopy in combination with the magic‐angle spinning (MAS) technique was applied to a series of Phalaenopsis tissues, including the leaf, sheath, stem, and root, at different growth and spiking periods. Compared with{¹H}/¹³C cross‐polarization MAS spectra, the ¹³C single‐pulse excitation MAS spectra displayed very distinct spectral patterns, recognizable as fingerprints of the tissues studied. ¹Here, we demonstrate that solid‐state ¹³C single‐pulse excitation NMR spectroscopy provides a direct and robust analytical tool for studying the various tissues of Phalaenopsis in different growth and spiking induction periods.     

TiO2 Thin Film with Varied Porous Structure Applied on the Degradation of Methylene Blue

In this study, porous TiO₂ thin films were prepared by the sol‐gel method employing polyethylene glycol 1000 (PEG 1000) as an organic template. Pore sizes were adjusted by varying the concentration of PEG 1000. The optimal PEG concentration range required to form TiO₂ films with a regular porous structure was investigated and was found to be 0.01–0.015 M. As the PEG 1000 concentration increased, the surface of these films became rougher because of larger pores. Degradation of methylene blue (MB) under UV irradiation was used to determine the photocatalytic activity of the films. In addition, the effect of the pH value of the MB solution on the films was evaluated by controlling its pH value at 5, 7, and 9. The results showed that the photocatalytic activity was correlated to the pore size and pore density of the thin films. TiO2 thin films possessing pore sizes in the diameter range of 35–85 nm exhibited the best conversion of 98% after 8 h of UV irradiation when the pH value was 7.     

Influence of cellulose nanofibers on the curing behavior of epoxy/amine systems

Epoxy composites were prepared using diglycidyl ether bisphenol F and water-dilutable diglycidyl ether bisphenol A with curing agents, polyoxypropylenediamine and diethylmethylbenzenediamine, in water or dimethylformamide as a solvent. The influence of cellulose nanofibers and solvents on curing kinetics of epoxy composites was investigated. Curing kinetic parameters were calculated using the model-fitting methods and the isoconversional method. Among these, the Sestak–Berggren equation best fit the experimental data. Results indicated that dimethylformamide decreased the reaction rate, whereas water revealed the opposite pattern. Cellulose nanofibers catalyzed the reaction between bisphenol F resins and the aromatic curing agent.     

K2CO3-Promoted Domino Reactions for Synthesis of Isocoumarins Under Microwave Irradiation

A small library of isocoumarin derivatives has been synthesized via K₂CO₃-catalyzed domino reactions of 2-carboxybenzaldehyde and ω-bromoacetophenones under microwave irradiation (MW). This strategy offers a simple, environmentally acceptable route to synthesize isocoumarin derivatives in moderate to excellent yields. All new compounds were characterized by ¹H NMR, ¹³C NMR, infrared, and high-resolution mass spectroscopic techniques.     

Determination of 129I in cement-solidified radwastes using neutron activation

The purpose of this study is to develop a neutron activation method to determine trace amounts of ¹²⁹I in cement-solidified radwastes. The radwaste samples were alkaline fused using KOH and then ¹²⁹I and iodine carrier were chemically separated by solvent extraction before and after neutron irradiation. Both stable iodine (¹²⁷I) and ¹²⁹I can be activated by neutrons through ¹²⁷I (n, 2n) ¹²⁶I and ¹²⁹I (n, γ) ¹³⁰I reactions; their activated radionuclides were counted together with a high-purity germanium detector. The chemical recovery yields ranged from 30 to 60 %, and it was found that more than 99.9 % of interfering radionuclides can be removed using solvent extraction after neutron irradiation. The minimum detectable amounts can be lowered to less than 1 mBq g^?1, which is superior to low energy γ-ray spectrometry by a factor of >10², on average. The established technique can be applied to re-evaluation of ¹²⁹I content in radwastes that can be re-classified to lower classes, and the cost for designing a final disposal facility can be significantly reduced.     

Synthesis and mesomorphism of 4,4'-bis(omega-hydroxyalkoxy)-alpha-methylstilbenes

A homologous series of 4,4'-bis(omega-hydroxyalkoxy)-alpha-methylstilbenes, denoted HAMS-n, has been synthesized. Here n is the carbon atom length of the peripheral n-alkyl chain; in this work n = 2 to 8 and 11. The composition, microstructure, thermal properties, and mesomorphism of the homologues were determined using elemental analysis, ¹H NMR, FTIR, DSC, wide angle X-ray diffraction, and polarizing optical microscopy with a heating stage. The influence of the length and the even/odd numbers of methylene units of the peripheral chains on the variants of mesomorphism and the stability of mesophases, as well as on their transition temperatures, are discussed. The homologues with n = 8 and 11 were enantiotropic monomorphic, CrG (or CrH). The odd homologues showed monotropic trimorphism on cooling, while the even homologues exhibited enantiotropic trimorphism. A pronounced even/odd effect on the melting temperatures was observed.