Targeting of AUF1 to vascular endothelial cells as a novel anti-aging therapy.

BACKGROUND: Inhibition of aging of vascular endothelial cells (VECs) may delay aging and prolong life. The goal of this study was to prepare anti-CD31 monoclonal antibody conjugated PEG-modified liposomes containing the AU-rich region connecting factor 1 (AUF1) gene (CD31-PILs-AUF1) and to explore the effects of targeting CD31-PILs-AUF1 to aging VECs. METHODS: The mean particle sizes of various PEGylated immunoliposomes (PILs) were measured using a Zetasizer Nano ZS. Gel retardation assay was used to confirm whether PILs had encapsulated the AUF1 plasmid successfully. Fluorescence microscopy and flow cytometry were used to quantify binding of CD31-PILs-AUF1 to target cells. Flow cytometry was also used to analyze the cell cycles of aging bEnd3 cells treated with CD31-PILs-AUF1. We also developed an aging mouse model by treating mice with D-galactose. Enzyme-linked immunosorbent assay (ELISA) was used to evaluate the levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). The malondialdehyde (MDA) and the superoxide dismutase (SOD) levels were detected by commercial kits. Hematoxylin-eosin (HE) staining was used to determine whether treatment with CD31-PILs-AUF1 was toxic to the mice. RESULTS: CD31-PILs-AUF1 specifically could targeted bEnd3 VECs and increased the percentage of cells in the S and G2/M phases of aging bEnd3 cells. ELISA showed that content of the IL-6 and TNF-α decreased in CD31-PILs-AUF1 group. The level of SOD increased, whereas MDA decreased in the CD31-PILs-AUF1 group. Additionally, CD31-PILs-AUF1 was not toxic to the mice. CONCLUSION: CD31-PILs-AUF1 targets VECs and may delay their senescence.

[Investigation of nascent polypropylene in-reactor alloy particles].

Heterogeneous nascent particles were observed in a pilot product of polypropylene in-reactor alloy, which was polymerized by Ziegler-Natta/Metallocene hybrid catalyst using Spheripol technology. Most of the particles in the product are translucent, and opaque particles were observed as well. The differences in morphology, composition, chain structure, thermal properties and mechanical properties between these two kinds of particles were investigated by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), polarized optical microscopy (POM), and differential scanning calorimetry (DSC) techniques. The results of FTIR, NMR and SEM indicate that different morphology of these two different particles is caused by different content of ethylene-propylene copolymers. The results of DSC and POM showed that the translucent particles has higher crystallization rate than opaque particles due to the presence of ethylene-propylene copolymers. The mechanical properties results showed that the impact resistance property of opaque particles is obviously lower than that of translucent particles, while its tensile strength and bending modulus are much higher than that of translucent particles. Based on the process of Spheripol technology, a preliminary explanation for the formation of different nascent PP in-reactor alloy particles is proposed.

[Investigation of the chain structure and thermal property of xylene solubles of impact polypropylene copolymers].

Impact polypropylene copolymers (IPC) are in-situ blends of polypropylene homopolymer and ethylene-alpha-olefin copolymers formed in the reactor, which is a multiphasic complex material with isotactic polypropylene (iPP) as a matrix in which poly(ethylene-alpha-olefin) elastomeric copolymer is finely dispersed, and ethylene-alpha-olefin random copolymer (EPR) acts as an elastomer to improve the impact resistance properties of iPP at room temperature and low temperature. In the present, the content of xylene soluble is used to evaluate the content of EPR rubber phase in IPC. The content, the chain structure, and glass transition temperature (T(g)) of EPR rubber are critical to the toughness of IPC. In the present report, Fourier transform infrared spectroscopy(FTIR), nuclear magnetic resonance (NMR) and differential scanning calorimetry(DSC) were utilized to study the comonomer content, chain structure and thermal property of xylene soluble of two IPC prepared by different catalysts. The results indicated that there are small amount of ethylene-propylene segmented copolymers containing short methylene sequence that is crystallizable in the xylene soluble in addition to the ethylene-propylene random copolymers. And the sequence length of crystallizable methylene group of ethylene-propylene segmented copolymers in these two kinds of xylene soluble is different. The random distribution degree of ethylene and propylene monomer in the ethylene-propylene copolymers in these two kinds of xylene soluble is similar. The xylene soluble with lower content of PPP sequence and higher content of ethylene monomer has lower T(g), which will benefit the improvement of impact resistance property of polypropylene.

[Investigation of N-hexadecylated poly (p-phenylene terephthamide) by infrared spectroscopy].

N-hexadecylated poly(p-phenylene terephthamide) (PPTA) comb-like polymers (PPTAC16), which are composed of PPTA backbone and hexadecyl side chains, were prepared by method of N-alkylation reaction. The molecular structure and thermal transition behavior of PPTAC16 were characterized by a combination of differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR) technique. DSC results indicated that the crystallization of hexadecyl side chains, and the side chain crystallization is less perfect than that of n-hexadecane crystal. IR results showed that the ordered degree of the packing of CH2 group in the side chain crystallization is lower than that of n-hexadecane crystal. Variable temperature IR spectroscopic results revealed that the stretching vibration and bending vibration bands of methylene group experience an abrupt change with increasing of temperature which indicate the melting of the side chain crystallization, furthermore the main chain of PPTAC16 was found to undergo an irreversible change accompanying the melting of the alkyl side chain crystallization. And the molten state of CH2 group in the hexadecyl of PPTAC16 is different from that of liquid n-hexadecane.

[Investigation of N-hexadecylated polycaprolactam by infrared spectroscopy].

N-hexadecylated polycaprolactam (PA6) comb-like polymers (PA6C16) with different alkylation degree, were synthesized using the method of N-alkylation reaction. The thermal transition behavior of these polymers were characterized by a combination of differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). DSC results indicated that the hexadecyl side chain can crystallize. Furthermore, the melting point of the hexadecyl side chain crystallization of the sample with high alkylation degree(PA6C16-H) is lower than that of sample with lower alkylation degree(PA6C16-L). FT-IR spectroscopic results showed that the methylene groups of the hexadecyl side chain of PA6C16-L tend to crystallize in orthorhombic form, while the methylene groups of the hexadecyl side chain of PA6C16-H tend to be packed into hexagonal form. Variable temperature IR spectroscopic results revealed that accompanying the melting of the side chain crystallization, the backbones of PA6C16-H undergo a conformation transition, while the conformation of backbones of PA6C16-L shows no obvious transition.

[Investigation on degradation of polypropylene/stabilizers composites irradiated by gamma rays].

The degradation behavior of polypropylene and polypropylene/stabilizer composites, caused by gamma radiation, was studied in the present work The stabilizers used were hindered phenol antioxidant and hindered amine light stabilizer. FTIR spectroscopy and DSC analysis were used to determine the structural variation induced by gamma radiation. It can be seen that the evolution of PP and composites PP/stabilizers on gamma irradiation is an increase in absorbance in the hydroxyl and carbonyl absorption regions. Carbonyl index calculated from FTIR spectra was used to characterize the rate of degradation. When the irradiation dose was small (<50 kGy), the degradation of pure polypropylene and polypropylene/stabilizers composites was not obvious; while the irradiation dose increased (> or =50 kGy), the carbonyl indexes of all the samples increased obviously, and the degradation degree of polypropylene/stabilizer composites was bigger than pure polypropylene. This result might be partially attributed to the molecular chain scission of hindered phenol and hindered amine under larger irradiation dose. The chain scission of stabilizers forms hydroperoxides and peroxide radicals, catalyzing the degradation of polypropylene. As the irradiation dose was small (<50 kGy), the crystallization temperatures of pure polypropylene and polypropylene/stabilizer composites all showed no remarkable changes; as the irradiation dose exceeded 50 kGy, the crystallization temperatures of pure polypropylene and polypropylene/stabilizer composites all decreased obviously. Correspondingly, the melting peaks of both pure polypropylene and polypropylene/stabilizer composites moved to lower temperature and split into two peaks with increasing the irradiation dose. The decrease of crystallization and melting temperatures might be attributed to the destruction of chemical structure and stereo-regularity of the molecular chain, due to the increasing of carbonyl and hydroxyl groups brought by the oxidation of polypropylene molecular chain. At the same irradiation dose (> or = 50 kGy), the crystallization and melting temperatures of polypropylene/stabilizer composites were lower than that of pure polypropylene. It indicates that the stabilizers accelerate the degradation of polypropylene. The results were accordant with the IR results.

[Study on microstructure of J-aggregates of cyanine dyes].

In the present paper, the J-aggregate structures of three types of cyanine dyes adsorbed both on 0.4 microm AgBrI cubic crystal surface (100) and on 1.8 microm AgBrI tabular crystal surface (111) were studied by use of atomic force microscope (deltaFM). Several types of aggregation structures were observed for the three types of dyes on AgBrI crystals. Rectangular structure was formed on the crystal faces of (100) and (111) for both anionic and cationic cyanine dyes. On the surface of anionic-cationic cyanine dyes, however, herringbone stacking structure was formed, and a banded spectrum was correspondingly detected on the AgBrI crystal surface.

[Study of spectral properties of J-aggregates of mixed cyanine dyes].

The J-aggregates and the photosensitive properties of two kinds of mixed cyanine dye and the corresponding independent cyanine dyes absorbed on AgBr cubic microcrystal were investigated. The reflection spectra of the J-aggregates of the mixed cyanine dyes and the corresponding independent cyanine dyes were measured by the use of UV-Vis spectroscopy. The results showed that the absorption band of the mixed J-aggregates absorbed on AgBr cubic microcrystal had two-peak wavelengths and accorded with the independent cyanine dyes, respectively. The sensitive performance of the mixed cyanine dyes was much enhanced compared to the corresponding cyanine dyes.

[Investigation on photooxidative degradation of polypropylene/organomontmorillonite nanocomposites].

Photooxidation degradation of polypropylene (PP)/organomontmorillonite (OMMT) nanocomposites was studied under UV irradiation at wavelength 365 nm. The OMMT was dispersed homogeneously in the PP matrix. The structural variation induced by photooxidation was detected by FTIR spectroscopy. It can be seen that the evolution of PP and nanocomposites PP/OMMT on irradiation is an increase in absorbance in the hydroxyl and carbonyl absorption regions. Carbonyl index was used to characterize the rate of photooxidative degradation. At the early stage of irradiation (shorter than 11 hours), the rate of photooxidative degradation of PP/OMMT nanocomposites was much faster than that of pure PP. With the increase in the irradiation time, the rate of photooxidative degradation of PP/OMMT nanocomposites became slower than that of pure PP. On the other hand, the OMMT content can also influence the photooxidative degradation rate. The variation in the photooxidative degradation rate is proposed to originate from the competition between the light shielding effect and accelerating photo-oxidative degradation effect of organomontmorillonite. These two effects play roles in the photooxidation process of PP simultaneously. At the early stage of irradiation, the accelerating photooxidative degradation effect dominates. With the increase in the irradiation time, the active sites such as SiOH, --OH etc and transition metal ions (Fe2+, Fe3+ etc) in the OMMT which can accelerate photooxidation are gradually consumed, and then the light shielding effect may play the main role. The method of curve-fitting was used to characterize the influence of organomontmorillonite on the photooxidative degradation products. Compared with pure PP, the content of products of carboxylic acid and anhydride were found to increase, whereas that of ester decreases in PP/OMMT nanocomposites.

[Investigation on effect of PVP on morphological changes and crystallization behavior of nylon 6 in PVP/nylon 6 blends by FTIR spectroscopy].

Temperature-dependent FT IR, DSC and POM were used to investigate the interaction between PVPK90 and nylon 6 molecules and its effect on the thermal behavior and morphology of nylon 6. DSC results suggest that the melting and crystallization behavior of nylon 6 are obviously influenced by the introduction of PVP. With the PVP content increasing, the crystallization temperature, melting temperature and the crystallinity of nylon 6 decreased, and eventually, both the exothermal and endothermic peaks could not be observed when the PVP content reached 80%, implying that the aggregation structure of nylon 6 changes from the crystalline state to the amorphous state. FTIR provided the evidence of the interaction between PVP and nylon 6 molecules. With the increase in PVP content, the peak position of nu N-H of nylon 6 gradually shifts from 3311 to 3300 cm(-1) with 90% content of PVP, and the half height peak width is broadened correspondingly. Three peaks were obtained in the carbonyl group absorption band for PVPK90/Nylon 6(50/50) and PVPK90/Nylon 6(80/20) blends from the curve-fitting results. With the addition of PVP molecules, the nu C=O of nylon 6 shifts to higher wave number and a new peak located at about 1620 cm(-1) appears and its peak area increases with the content of PVP. The above spectral variation of nu C=O and nu N-H in the PVPK90/Nylon 6 blend indicates that the carbonyl group of PVP could form H-bonding with N-H group of nylon 6 molecule, and partially destroy the hydrogen bonding between the nylon 6 molecules. POM results showed that the spherulitic size of nylon 6 decreases with the increment of the PVP and becomes more imperfect, and when the PVP content reaches 80%, no spherulites could be observed. This phenomenon is attributed to the molecular interactions between the PVP and the nylon 6 molecules, which weakens the free mobility of nylon 6 chains to form regular packing and eventually induces the change in the spherulitic morphology of nylon 6. In summary, the molecular interactions between the carbonyl group of PVP molecules and N-H group of nylon 6 molecules account for the above changes in the crystalline structure and the morphology of nylon 6 in the blends.

[Investigation on composites of europium fluorescent complexes and polyvinylpyrrolidone].

In order to investigate the relationship between the aggregation structure and fluorescence properties of composites of rare earth fluorescent complexes and polymers, the fluorescent complexes of Eu(TTA)3 x 2H2O and Eu(TTA)3 x (TPPO)2 were synthesized by the reaction of TTA (2-thenoyltrifluoroacetone), TPPO (triphenylphosphine oxide) and EuCl3, and their composites with polyvinylpyrrolidone (PVP K30) were prepared. The fluorescence spectroscopy, FTIR spectroscopy and TEM were used to characterize these composites. Fluorescence spectroscopy results indicated that the fluorescence intensity of the PVP/Eu(TTA)3 x 2H2O composites is obviously improved compared with that of the Eu(TTA)3 x 2H2O complexes. For the composites with the molar ratio of the complexes to the repeat unit of PVP being 1:35, the intensity of 612 nm emission peak of the composites is 5.5 times for PVP/Eu(TTA)3 x 2H2O and 0.3 times for PVP/Eu(TTA)3 x (TPPO)2 higher than that of the corresponding pure rare earth fluorescent complexes. And the emission intensity ratio of 612 to 590 nm peak is 14.7 in PVP/Eu (TTA)3 x 2H2O composite, larger than that of Eu(TTA)3 x 2H2O complexes. These results suggested that the luminescent properties of the europium fluorescent complexes were obviously enhanced in the presence of PVP matrix and there are interactions between the fluorescence complexes and PVP molecules. In the presence of PVPK30, the FTIR spectra of the Eu(TTA)3 x 2H2O complexes were obviously influenced as well. Based on the curve-fitting results of IR spectra of PVP/Eu(TTA)3 2H2O composites with the molar ratio of repeat unit of PVP to Eu(TTA)3 x 2H2O being 7:1 and 2:1, multiple absorption peaks of nu C=O are observed. The IR spectral variations indicated that there are coordination interactions between Eu3+ ions and the carbonyl groups of PVP, and multiple coordination fashion exists. TEM results showed that there are microphase separation structures in PVP/Eu(TTA)3 x 2H2O and PVP/Eu(TTA)3 x (TPPO)2 composites. The microphase separation phenomenon in composite of PVP/Eu(TTA)3 x (TPPO)2 is more obvious than that of the PVP/Eu(TTA)3 x 2H2O. And the Europium complexes are in amorphous state, which further proved the interactions between PVP molecules and the rare earth fluorescence complexes Eu(TTA)3 x 2H2O and Eu(TTA)3 x (TPPO)2.

[Fluorescence spectra of J-aggregates of anionic-cationic cyanine dyes].

In the present paper, the fluorescence spectral curves of J-aggregates of two kinds of anionic-cationic cyanine dyes adsorbed on AgIBr cubic microcrystals were measured by using fluorescence spectroscopy, and compared with the sensitivity characteristic of anionic-cationic cyanine dyes. The results show that the peaks of fluorescence spectral curves of anionic-cationic cyanine dyes were lower than that of anionic and cationic cyanine dyes, and the higher sensitivity efficiency was due to the fact that more electrons transfer to the surface of AgIBr microcrystal.

[Investigation on the fluorescence spectroscopy of normal and malignant rectum tissues].

In the present article the fluorescence characteristics of normal and malignant rectum organ tissues of 12 samples were investigated in vitro using UV (200-400 nm) fluorescence spectroscopy and compared with the results of the infrared spectra of normal and malignant rectum organ tissues. The results showed that the fluorescence intensity of normal rectal tissue was higher than that of rectal malignant tissue. The difference in fluorescence intensity at 492 and 544 nm between normal rectal tissue and malignant tissue may be considered as a detection criterion.

[New fluorescent staining method to distinguish normal and malignant rectum tissues using terbium (III)-ciprofloxacin complex].

A new fluorescent staining method to distinguish normal and malignant rectum tissues using terbium(III)-Ciprofloxacin complex was investigated. The terbium (III) complex exhibits strong fluorescence and the staining process with the complex is very fast. It needs 3-5 minutes. The results showed that the fluorescence microscope images were similar to the images stained using traditional hematoxylin and eosin (H&E) methodology. The fluorescence spectra and FTIR spectra of normal and malignant rectum tissues were collected and the detection criterions for the malignant rectum tissues were the same as the staining results. In summary, the fluorescence staining may be developed as a simple and convenient method.

[Characterization of the orientation of polymer material by non-polarized raman laser light spectroscopy].

The non-polarized Raman laser light was used to investigate the anisotropic polymers including polypropylene fiber, nylon 6 flat fiber, and polyethylene pipe. The Raman spectra of the same samples with different location relative to the incident direction of laser beam show obvious differences. The present result extends the application of Raman spectroscopy to the characterization of oriented polymers samples.

[Investigation of PP/PE blend with FTIR mapping].

The polypropylene/polyethylene (PP/PE) blends with different weight ratio were studied by FTIR spectroscopy. The characteristic absorption bands of PP and PE in different blends were compared. It was found that the ratio of the characteristic absorption peak areas of PP to those of PE is correlated with the weight ratio of PP to PE in the blends. Based on the above results, FTIR mapping technique was applied to characterize the samples prepared by embedding PP fiber into molten PE film, and the distribution of PP and PE in the blends can be obtained from the ratio of the characteristic peak areas of PP to PE. Good agreements have been observed between the IR mapping image and the image obtained using polarized optical microscope. These results indicated that FTIR mapping technique is an effective tool to investigate the phase separation behavior of polymer blends based on the ratio of the characteristic peak areas of different polymers.