The Sensitized Quantum Yield at Photodehydrogenation Reaction of Abietic Acid

The re-cycled irradiation of abietic acid above 300 nm with benzophenone and copper(ii) pivalate in toluene solution has resulted in conversion to dehydroabietic acid with a quantum yield ranging from 9.6 to 5.5. The high quantum yield may be attributed to the re-generation of benzophenone by means of the electron transfer reaction of benzophenone radical and to some additional reactions on formation of dehydroabietic acid.     

歧化松香中树脂酸异构体的NMR研究

树脂酸是松香的主要成分,歧化松香质量的好坏,主要取决于树脂酸的组分及其含量.本文测定了五种树脂酸——枞酸、新枞酸、左旋海松酸、长叶松酸和脱氢枞酸的¹H、¹³C、DEPT谱.并通过二维HMQC以及HMBC相关谱和模型化合物分别对其谱图的归属进行了详细的探讨.     

A promising red-emitting phosphor for white-light-emitting diodes prepared by a modified solid-state reaction

Using urea, boric acid and polyethylene glycol (PEG) as auxiliary reagents, the novel red-emitting phosphors Ca₁₉Zn₂ (PO₄)₁₄:Eu³⁺ have been successfully synthesized by a modified solid-state reaction. Thermogravimetric (TG) analysis, X-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence (PL) spectra were used to characterize the resulting phosphors. The dependence of the photoluminescence properties of Ca₁₉Zn₂ (PO₄)₁₄:Eu³⁺ phosphors upon urea, boric acid and PEG concentration and the quadric-sintered temperature were investigated. Luminescent measurements showed that the phosphors can be efficiently excited by ultraviolet (UV) to visible region, emitting a red light with a peak wavelength of 616 nm. The material has potential application as a fluorescent material for ultraviolet light-emitting diodes (UV-LEDs).     

ToF-SIMS characterisation of diterpenoic acids after chromatographic separation

Microcolumn liquid chromatography (μHPLC) coupled on-line with time of flight secondary ion mass spectrometry (ToF-SIMS) was applied for mixture of diterpenoic acids (abietic, gibberellic and kaurenoic) analysis. Chromatographic effluent, with analytes separated, was carried out directly onto different, ToF-SIMS compatible surface substrates, for further ToF-SIMS analysis. Silica gel Si₆₀, aluminium backplate modified Si₆₀, monolithic silica gel and Raman spectroscopy chromatographic thin layers were used as the deposition substrates in this experiment. By ToF-SIMS surface imaging the deposition trace picture has been obtained. Effluent deposition surface area was scanned for diterpenoic acid fragment mass values based on mass spectrometric library. Measured ToF-SIMS dataset of fragment abundance and intensities were used for preliminary fragmentation schemes construction. The lowest substrate background activity has been established for monolithic silica gel thin layer and aluminium backplate modified Si₆₀ thin layer. In the case of Raman spectroscopy pre-treated thin layer or conventional chromatographic thin layer Si₆₀, the both, high background signal intensity and impossibility to construct negative ions surface image, were observed. Diterpenoic acids studied serve the similar mass spectrum but ToF-SIMS coupled with liquid chromatographic separation brings new impact to the positive identification of analytes studied.     

Induced assembly and photoluminescence of lanthanum (Tb, Eu, Dy) complexes/ZnO/polyethylene glycol hybrid phosphors

Some novel kinds of hybrid phosphors were assembled with lanthanum (Tb, Eu, Dy) complexes (with four kinds of terbium complexes is 2,4-dihydroxybenzonic acid (DHBA), 1,10-phenanthroline (phen), acetylacetone (AA) and nicotinic acid (Nic), respectively) doped ZnO/PEG particles by co-precipitation approach derived from Zn(CH₃COO)₂ (Zn(AC)₂), NaOH, PEG as precursors at room temperature. The characteristic luminescence spectra for f-f transitions of Tb³⁺, Eu³⁺, Dy³⁺ were observed. It is worthy to point out that ZnO is the excellent host for lanthanum ions by the assembly of PEG matrices.     

Laws governing the combustion of the Ni + Al system under a low ambient gas pressure

The ambient pressure dependences of the combustion rate and combustion-induced elongation for an initial Ni + Al mixture and Ni + Al mixtures subjected to vacuum heat treatment (VHT), mechanical activation, and additional activation in water (dispersion) have been studied. Most of the studies have been conducted for mixtures based on PNK-brand nickel (carbonyl); a separate set of experiments has been conducted for PNE-brand nickel (electrolytic). These powder brands contain different amounts of impurity gases and have different particle sizes. It has been shown that VHT, the ambient gas pressure, and the type of the used nickel have a substantial effect on the combustion rate of these mixtures. For the mixtures based on PNK nickel, the increase in the combustion rate after VHT is more significant than that after mechanical activation despite a more thorough mixing of the precursors and changes in the mixture microstructure. The qualitative change in the behavior of the dependence of the combustion rate of the dispersed mixtures on the external gas pressure has been interpreted in terms of a convective–conductive combustion model. The studies have made it possible to prove the previously made conclusion about the gasless combustion of Ni + Al mixtures (PNK nickel) under high ambient gas pressures.     

Self‐Assemble Polymeric Nanoparticle with GSH Exhaustion for SPECT Imaging–Guided Enhanced Radioisotope Therapy

Exploiting biocompatible nanomaterials for cancer theranostics has attracted great attention in recent years. Herein, a multifunctional self‐assembled nanoparticle based on a biocompatible polymer that contains 3‐(4‐hydroxyphenyl) propionic acid N‐hydroxysuccinimide ester (HOPA) for radiolabeling and piperlongumine (PL) for exhausting endogenous glutathione (GSH) (HOPA‐C18PMH‐PEG/PL) is successfully synthesized. With radionuclide ¹²⁵I labeling, SPECT imaging shows high tumor uptake of HOPA‐C18PMH‐PEG/PL after intravenous injection. The in vitro and in vivo combined radioisotope therapy (RIT) and chemotherapy using ¹³¹I‐labeled HOPA‐C18PMH‐PEG/PL is then carried out, achieving synergistic antitumor effect. This is because the reactive oxygen species (ROS) level in the tumor sites of mice treated with ¹³¹I‐labeled HOPA‐C18PMH‐PEG/PL is increased after the exhaustion of GSH by PL. Additionally, such a strategy (exhausting GSH and increasing ROS) induces no obvious toxicity to normal tissue. Therefore, as‐made polymeric nanoparticles exhibit multifunctional properties for SPECT imaging–guided combined RIT and chemotherapy in one system. This finding will further promote polymeric nanoparticle–based RIT of cancer and is expected to be used for future clinical transformation.     

双波长倍增差示法测定双嘧啶片中磺胺嘧啶和甲氧苄啶的含量

本论述了双波长倍增差示法同时测定了双嘧啶片中磺胺嘧啶（ＳＤ）和甲氧苄啶（ＴＭＰ）的含量，本法是基于测定标准溶液ＳＤ（８～１４）×１０＾－６ｇ／ｍＬ，ＴＭＰ（１～２）×１０＾－６ｇ／ｍＬ，和样品溶液在２４２．５ｎｍ和２２８．０ｎｍ处的吸收度。ＳＤ和ＴＭＰ的平均回收率与ＲＳＤ分别为１００．６０％，０．３３％，和９８．２７％，１．５８（ｎ＝２０）。本法简便快捷，结果满意。     

Evaluation of the Complexation Process Between Poly(Aspartic Acid) and Poly(Ethylene Glycol) Through Dynamic Rheology and Electrokinetic Potential

Investigations concerning the interactions between the polymeric pair constituted of poly(aspartic acid) (PAS) as a proton-donating polycarboxilic acid and poly(ethylene glycol) (PEG) as a proton-accepting compound are continued from previous studies. The complexation between PAS and PEG has potential use as a matrix for encapsulation of bioactive substances with potential biomedical applications. The interactions that occurred were monitored in dilute solutions by determining the particle size distribution and the zeta potential (ZP) through laser light scattering method; data associated with oscillatory rheology was used as a complementary analysis. The influence of the ratio between the components and the temperature conditions during the complexation process brought additional data concerning the intermolecular links formed through hydrogen bonds.     

枞酸十二醇酯琥珀酸酐的合成与表征

以枞酸为起点 ,合成了十二醇酯琥珀酸酐 ,采用红外光谱、核磁共振波谱及质谱对中间产物及终产物进行了结构表证。     

Viscosity,Ultrasonic, and Refractometric Studies of Chitosan/Polyethylene Glycol Blend in Solution at 30, 40, and 50°C

Measurements of viscosity, ultrasonic velocity, refractive index, and density of chitosan (CS)/polyethylene glycol (PEG) blends in buffer solution (0.1 M acetic acid+0.2 M sodium acetate) were carried out for different blend compositions at 30, 40, and 50°C. Using the viscosity data, interaction parameters μ and α were computed to determine miscibility. These values revealed that the blend was miscible when the chitosan content was more than 60% of the blend. The results were further confirmed by ultrasonic velocity, density, and refractive index measurements. Further, the results revealed that the change in temperature has no significant effect on the miscibility of CS/PEG polymer blends.     

Surface spectroscopic imaging of PEG-PLA tissue engineering constructs with ToF-SIMS

Poly(lactic acid) (PLA) has been studied extensively in the field of tissue engineering due to its well-established biodegradability and biocompatibility. To improve its non-fouling properties we entrapped poly(ethyl glycol) (PEG), into the surface, which was characterised by a combination of ToF-SIMS and XPS. Cell attachment was subsequently investigated as a function of the amount of entrapped PEG. XPS was instrumental in quantifying the amount of PEG entrapped at higher concentrations, whereas the significantly higher sensitivity and superior imaging capabilities of ToF-SIMS enabled a full characterisation of the PEG distribution at the low concentrations required for the desired non-fouling properties, which were well below the XPS quantification limit. It was found that pronounced segregation effects leading to the formation of PEG-enriched domains ranging between ca. 5 and several tens of microns across were present at all PEG concentrations investigated.     

Sol-gel法制备CaSnO_3∶Eu~(3+)发光粉过程中添加PEG的作用

采用sol-gel法制备CaSnO3:Eu3+荧光粉。研究了在制备过程中添加表面活性剂聚乙二醇(PEG10000)对CaSnO3:Eu3+结构、粒度、形貌及发光性能的影响。通过X射线衍射(XRD)、激光粒度仪,扫描电镜(SEM)及荧光分光光度计对样品进行了表征。结果表明:在制备过程中添加PEG没有改变样品的结构,很好地改善样品粒度以及形貌,荧光粉的相对发光强度也稍有增强。     

Self‐Assembly of Drug–Drug Conjugates as Drug Self‐Delivery System for Tumor‐Specific pH‐Triggered Release

An acid‐labile doxorubicin dimer (D‐DOX) is designed as drug–drug conjugate for tumor intracellular pH‐triggered release, by conjugating doxorubicin (DOX) with adipic acid dihydrazide (ADH). The dimer‐based surfactants modified with polyethylene glycol (PEG), DOX‐ADH‐DOX‐PEG or are synthesized by mono‐PEGylation and bi‐PEGylation, respectively. Then the prodrug nanoparticles are fabricated with different drug contents via dialyzing the mixture solution of D‐DOX and the PEGylated surfactants in dimethyl sulfoxide (DMSO) with different mass ratios against water. It is found that the smaller prodrug nanoparticles (142–163 nm) could be obtained with the mono‐PEGylated surfactant, than those of 157–225 nm with the bi‐PEGylated surfactant. Furthermore, the mono‐PEGylated surfactant results in a higher drug content of 51% due to their lower PEG contents. All prodrug nanoparticles could release DOX completely within 36 h at pH 5.0, with the premature drug leakage of less than 10% at pH 7.4. The 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assays demonstrate the proposed drug self‐delivery system possessed an enhanced anticancer efficacy against HepG2 cells than the free DOX.     

Routine preparation of air-dried negatively stained and unstained specimens on holey carbon support films: a review of applications

Several representative examples are given of the successful application of negative staining across the holes of holey carbon support films using 5% (w/v) ammonium molybdate solution containing trehalose. The inclusion of 0.1% (w/v) trehalose is considered to be most satisfactory, although good data have also been obtained in the presence of 0.01 and 1.0% (w/v) trehalose. The examples given fall into the following groups: protein molecules in the absence of polyethylene glycol (PEG), protein molecules in the presence of PEG (Mr 1000), lipoproteins, lipids and membranes, filaments and tubules, viruses in the absence of PEG, viruses in the presence of PEG, aqueous polymer solutions, and finally for comparison purposes, four unstained samples studied in the presence of trehalose alone. In all these cases, and many others not documented here, successful spreading of the sample across holes has been achieved, with the sample embedded within a thin film of air-dried ammonium molybdate+trehalose. These specimens can be rapidly produced and provide an alternative to negatively stained specimens on carbon support films. Specimen stability in the electron bean is good and such specimens can usually generate superior negatively stained TEM images without flattening and adsorption artefacts. The formation of 2-D arrays/crystals of protein molecules and viruses, suspended across holes in the presence of ammonium molbybdate+trehalose, and trehalose alone, is also demonstrated.     

Molecular orientation of lyotropic nematic phase in a mixture of two non-mesogenic compounds

We report the results of our studies on the optical and thermal properties of the mixture of two non-mesogenic compounds, namely, sodium dodecyl sulfate (SDS) and glacial acetic acid (GAA). The mixture exhibits very interesting schlieren texture of lyotropic micellar nematic (N_D) phase, SmA and SmB phases, respectively, at different concentrations of SDS in GAA sequentially when the specimen is cooled from its isotropic phase. The order parameter (S) of the lyotropic micellar nematic (N_D) phase is estimated with the help of temperature dependence of optical anisotropy from the measured values of refractive index and density data. The experimental curve showing the temperature variation of order parameter is very well fitted with the Mayer–Saupe theoretical curve. X-ray studies have also been discussed. The formation of the above phases has been confirmed by optical and differential scanning calorimetry studies.     

The roles of hydrochloric acid and polyethylene glycol in magnetic fluids

Increasing interest has been drawn to the studies of magnetic fluids due to their multiple applications from industry to medicine. However, further exploration is still required for the techniques of preparing satisfying, convenient and stable magnetic fluids. We explored characteristics of magnetic liquids prepared by employing co-precipitation techniques of hydrochloric acid (HCl) and polyethylene glycol (PEG), and the functions of HCl and PEG in the magnetic liquid. According to the improved technique, after preparing Fe₃O₄ by a co-precipitation method, hydrochloric acid and PEG2000 react with magnetic particles at a certain temperature to generate the anticipated magnetic nanoparticles. The process could be under an air atmosphere rather than a N₂ atmosphere. Compared with traditional techniques, the magnetic nanoparticles prepared by this method have smaller size, better dispersion and stability, with the average hydrodynamic diameter adjustable between 8 and 50 nm. This study revealed that reduction of nanoparticles size is not mainly due to a [Cl⁻] coating over the magnetic nanoparticles, but that HCl reacts with Fe₃O₄ particles after being heated. Meanwhile, PEG can stabilize or coat Fe₃O₄ nanoparticles as a dispersing and stabilizing agent.     

Polyethylene glycol-assisted growth of Cu2SnS3 promising absorbers for thin film solar cell applications

In this paper, we report, for the first time, the results of the polyethylene glycol- (PEG) assisted preparation and characterization of high-quality and well-crystallized Cu₂SnS₃ (CTS) thin films obtained using sol–gel spin-coating method and a subsequent annealing in a sulphur atmosphere. Structural, morphological, compositional, electrical and optical investigations were carried out. The X-ray diffraction patterns of the samples proved the polycrystalline nature and preferred crystallization of the films. No peak referring to other binary or ternary phases were detected in the patterns. The intensity of the preferred orientation and crystallite size of the films increased with increasing PEG content. This trend yielded an improvement in photo-transient currents of the PEG-assisted growth of CTS films. The scanning electron microscopy images revealed that the CTS films have continuous, dense and agglomeration-like morphology. Through energy dispersive X-ray spectroscopy studies, it has been deduced that the samples consist of Cu, Sn and S of which atomic percentages were consistent with Cu/Sn and S/metal initial ratios. The agglomerated morphology of the samples has been attributed to increasing PEG content. A remarkable enhancement was observed in photo-transient currents of p-n junction of the produced films along with increasing PEG content. Through resistivity-temperature measurements, three impurity level electrical activation energy values for each film were found. Optical band gap values of the films were estimated via absorbance-wavelength behaviours and decreased with increasing PEG content. It has been revealed that PEG-assisted growth of CTS thin films is a promising way to improve its photovoltaic characteristics.     

Hyperfine interactions in the mixed ligand complexes of phenolic compounds with iron phthalimide

Six new mixed ligand complexes of iron phthalimide with gallic acid, pyridoxine, sulphosalicylic acid, salicylaldehyde, anisaldehyde, and naphthaldehyde have been prepared and characterised on the basis of conductance, magnetic susceptibility, IR, electronic and Mössbauer spectroscopic studies. The room temperature Mössbauer spectra exhibit a broad and asymmetric doublet which persists down to 50 K. The I. S. and Q. S. values indicate iron to be in +3 and high spin state. The magnetic moment values (～5.0 BM at 300 K decreasing to ～ 3.0 BM at 77 K) do not show any magnetic transition.     

聚乙二醇-硫酸铵双水相体系萃取分离镉(Ⅱ)

研究了硫酸铵-聚乙二醇2000双水相体系中Cd2+的萃取行为,探讨了酸度、KI、乙基紫(EV)、(NH4)2SO4用量对于Cd2+萃取率的影响.实验表明:在(NH4)2SO4存在下,聚乙二醇与水分相时,无法分离游离的Cd2+,对CdI24-的分离也不完全,而同样条件下加入毫克级EV后,Cd2+与EV、I-形成三元缔合物...