Akt is involved in the inhibition of cell proliferation by EGF

Axin is a negative regulator of the Wnt/beta-catenin pathway and is involved in the regulation of axis formation and proliferation. Involvement of Axin in the regulation of other signaling pathways is poorly understood. In this study, we investigated the involvement of Akt in growth regulation by Axin in L929 fibroblasts stimulated by EGF. Akt activity was increased by EGF treatment and Ras activation, respectively. Both the EGF- and Ras-induced Akt activations were abolished by Axin induction, as revealed by both Western blot and immunocytochemical analyses. The proliferation and Akt activation induced by EGF were decreased by Axin induction, and the effects of EGF were abolished by treatment of an Akt-specific inhibitor. Therefore, Axin inhibits EGF-induced proliferation of L929 fibroblasts by blocking Akt activation.     

Friedel-Crafts Polymers. 6. Friedel-Crafts Polycondensation of p-Xylylerte Dibromide with Salicylic Acid and β-Resorcyiic Acid

Polymers were prepared by condensing p-xylylene dibromide separately with salicylic acid and β-resorcylic acid in the presence of anhydrous ferric chloride in dioxane. The polymer samples_were characterized by elemental analysis, by IR spectral study, by M determined by vapor pressure osmometry, by nonaqueous conducto-metric titration in pyridine, by TGA in air, and by viscosity measurements of polymer solutions in DMF. Polymeric metal chelates of Cu²⁺, Co²⁺, Zn²⁺, Ni²⁺, and Fe³⁺ with polymer samples were prepared and characterized by elemental analysis, by IR spectral study, and by TGA in air. The chelation ion-exchange properties of the polymer samples were studied by employing the batch equilibration method.     

Kinetic studies of free-radical polymerizations of I-vinylimidazole initiated by benzoyl peroxide and azoisobutyronitrile

Kinetic features of radical polymerizations of 1-vinylimidazole initiated by azoisobutyronitrile and by benzoyl peroxide have been investigated in several solvents and at several temperatures. Polymerizations initiated both by the azo compound and by the peroxide have abnormally low monomer exponents and abnormally high initiator exponents, features first noted by Bamford and Schofield and attributed by them to degradative addition of monomer. Polymerizations initiated by benzoyl peroxide appear to be further complicated by induced decomposition of the initiator; conversion vs time curves, especially for polymerizations in dimethylformamide and particularly at 80°C, show pronounced curvature. These curves can be approximately interpreted in terms of the Tobolsky theory of “dead-end” radical polymerization.     

Acetyl-CoA carboxylase beta expression mediated by MyoD and muscle regulatory factor 4 is differentially affected by retinoic acid receptor and retinoid X receptor

Mammals have two major isoforms of acetyl-CoA carboxyase (ACC). The 275 kDa beta-form (ACCbeta) is predominantly in heart and skeletal muscle while the 265 kDa alpha-form (ACCalpha) is the major isoform in lipogenic tissues such as liver and adipose tissue. ACCbeta is thought to control fatty acid oxidation by means of the ability of malonyl-CoA to inhibit carnitine palmitoyl-CoA transferase-1 (CPT-1), which is a rate-limiting enzyme of fatty acid oxidation in mitochondria. Previously, it was reported that MyoD and other muscle regulating factors (MRFs) up-regulate the expression of ACCbeta by interactions between these factors and several cis-elements of ACCbeta promoter. We described here that ACCbeta expression mediated by MRFs is regulated by retinoic acids. Endogenous expression of ACCbeta in differentiated H9C2 myotube was significantly increased by retinoic acid treatment. However, on transient transfection assay in H9C2 myoblast, ACCbeta promoter activity was suppressed by RXRalpha and more severely by RARalpha. These effects on ACCbeta expression in myoblasts and myotubes by RXRalpha and RARalpha seem to be mediated by their interactions with MRFs because no consensus sequence for RXRalpha and RARalpha has been found in ACCbeta promoter and retinoic acid receptors did not affect this promoter activities by itself. In transient transfection in NIH3T3 fibroblast, the activation of ACCbeta promoter by MyoD, main MRF in myoblast, was significantly suppressed by RARalpha and to a less extent by RXRalpha while the RXRalpha drastically augmented the activation by MRF4, major MRF in myotube. These results explained that retinoic acids differentially affected the action of MRFs according to their types and RXRalpha specially elevates the expression of muscle specific genes by stimulating the action of MRF4.     

Isotachophoretic zone formation of serum albumin in different free fluid electrophoresis instruments

The isotachophoretic behavior of a model protein, serum albumin, was examined (i) by computer simulation, (ii) by capillary isotachophoresis in HPE 100 and Tachophor 2127, (iii) by continuous flow isotachophoresis in Elphor VaP 22 and the BIO-STREAM Separator and (iv) by recycling isotachophoresis in an apparatus of our own design. Variations in monitored zone shapes can be explained by differences in engineering aspects and fluid stabilization principles of the instruments.     

History of the Development and Growth of Thermosetting Polymers

Fibrous proteins are cross-linked through the disulfide linkages of cystine; animal and vegetable proteins can be cross-linked by the reaction of tannic acid, chromic acid, or formaldehyde; and natural rubber can be vulcanized by heating with sulfur. However, most thermosetting polymers are synthetic polymers. These include saturated polyesters (Glyptals) synthesized by Smith in 1901, phenolic plastics produced by Baekeland in 1907, urea and melamine plastics produced by John and Henkel in 1918 and 1935, alkyds patented by Kienle in 1933, glycol maleates patented by Ellis in 1937, and epoxy resins patented by Schlack in 1933. Many of these developments were made prior to the advent of commercial synthetic thermoplastics. However, because their fabrication is more labor intensive than that of thermoplastics, thermosetting plastics now account for less than 20% of all plastics produced. Nevertheless, over 2.5 million tons of these thermosets are produced annually and the use of these cross-linked plastics continues to grow.     

High-performance liquid chromatography of sulphadimethoxine and its N1-glucuronide, N4-acetyl and N4-acetyl-N1-glucuronide metabolites in human plasma and urine

Sulphadimethoxine is metabolized in humans by N1-glucuronidation and by N4-acetylation. Sulphadimethoxine-N1-glucuronide can be measured by the direct high-performance liquid chromatographic analysis and without enzymic deglucuronidation. The N1-glucuronide can be measured by an isocratic as well as by a gradient mobile phase. The group contribution of the N1-glucuronide moiety to the capacity factor is a reduction of 0.24 in the isocratic system and 0.55 in the gradient system. N4-Acetylation increases the capacity factor by a factor 1.4 in the isocratic system and by 1.06 in the gradient system.     

Controlled Radical Polymerization

Various methods which lead to the control of molecular weight and polydispersities, and which allow for the preparation of block copolymers by radical polymerization are discussed. Thermal polymerizationof styrenes in the presence of stable radicals, polymerization of vinyl acetate and methyl methacrylate in the presence of chromium complexed by macrocyclic ligands polymerization of vinyl acetate initiated by organoaluminum compounds complexed by dipyridyl and activated by stable radicals, as well as in the presence of phosphites, are described in detail.     

Chlorophyll bleaching by UV-irradiation in vitro and in situ: Absorption and fluorescence studies

Chlorophyll bleaching by UV-irradiation has been studied by absorbance and fluorescence spectroscopy in extracts containing mixtures of photosynthetic pigments, in acetone and n-hexane solutions, and in aqueous thylakoid suspensions. Chlorophyll undergoes destruction (bleaching) accompanied by fluorescent transient formation obeying first-order kinetics. The bleaching is governed by UV-photon energy input, as well as by different chlorophyll molecular organizations in solvents of different polarities (in vitro), and in thylakoids (in situ). UV-C-induced bleaching of chlorophylls in thylakoids is probably caused by different mechanisms compared to UV-A- and UV-B-induced bleaching.     

Polymer modification to achieve novel properties

Polymers have been modified, by subjecting them to reactions in solution, in the melt and in the solid state. Novel polymers with improved and optimized properties have also been created by copolymerization, chain transfer or by the design of chain termination. Even by manipulating the initiation step in polymerizations, functional and reactive groups have been introduced at the head of the polymer chain. Polymer properties have been modified by influencing physical properties of polymers by orienting, annealing and blending.     

铂修饰光阴极及其在纳晶太阳能电池中的应用

分别用真空镀膜法、热分解法和电化学法制备了铂金修饰导电玻璃,并以此作为光阴极组装了染料敏化纳晶TiO₂太阳能电池.用SEM观察了铂金修饰导电玻璃表面形貌,发现用真空镀膜法制备的铂金膜结构缺陷多、不均匀,存在较多的污点.用热分解法制备的铂金膜具有多孔状结构,但存在较多的有机物分解的残留物.用电镀法制备的铂金膜结构均匀、排列规则、缺陷少、污染少.测定了所制备铂金膜的电阻,结果表明由电镀法所制得的铂金膜电阻最小,用热解法和真空镀膜法制得的铂金膜电阻较大.测定了DSSC电池的光电性能,发现用电镀法制得的铂金膜的催化性能最好,大大提高了DSSC电池的性能;其次是热分解法,由真空镀膜法制备的铂金膜对电池的性能没有多大改善.     

Friedel-Crafts Polymers. 5. Friedel-Crafts Polycondensation of p-Xylylene Dichloride with Salicylaldehyde and o-Hydroxyacetophenone

Polymers were prepared by condensing p-xylylene dichloride (PXDC) separately with salicylaldehyde (SAL) and o-hydroxy-acetophenone (OHAC) in the presence of anhydrous ferric chloride in dioxane. The polymer samples were characterized by elemental analysis, measurement of their M by vapor pressure osmometry, by nonaqueous conductometric titration in pyridine, by IR spectral study, by TGA in air, and by viscometric study in DMF. The ion-exchange capacities of these polymeric ligands for selected metal ions were measured by the batch equilibration method and compared. Polymeric metal chelates of PXDC-SAL and PXDC-OHAC polymer samples with Cu^{2 +}, Ni²⁺, Co²⁺, Fe³ and Zn^{2 +} were prepared and characterized by elemental analyses, by IR spectral study, and by thermal analyses.     

Cytosolic accumulation of gammaH2AX is associated with tropomyosin-related kinase A-induced cell death in U2OS cells

Tropomyosin-related kinase A (TrkA) plays an important role in cell survival, differentiation, and apoptosis in various neuronal and nonneuronal cell types. Here we show that TrkA overexpression by the Tet-On system mimics NGF-mediated activation pathways in the absence of nerve growth factor (NGF) stimulation in U2OS cells. In addition, p53 upregulation upon DNA damage was inhibited by TrkA, and p21 was upregulated by TrkA in a p53-independent manner. TrkA overexpression caused cell death by interrupting cell cycle progression, and TrkA-induced cell death was diminished in the presence of its specific inhibitor GW441756. Interestingly, TrkA-mediated cell death was strongly related to gammaH2AX production and poly (ADP-ribose) polymerase cleavage in the absence of DNA damage inducer. In this study, we also reveal that gammaH2AX production by TrkA is blocked by TrkA kinase inhibitors K-252a and GW441756, and it is also significantly inhibited by JNK inhibitor SP600125. Moreover, reduction of cell viability by TrkA was strongly suppressed by SP600125 treatment, suggesting a critical role of JNK in TrkA-induced cell death. We also found that gammaH2AX and TrkA were colocalized in cytosol in the absence of DNA damage, and the nuclear localization of gammaH2AX induced by DNA damage was partly altered to cytosol by TrkA overexpression. Our results suggest that the abnormal cytosolic accumulation of gammaH2AX is implicated in TrkA-induced cell death in the absence of DNA damage.     

Theoretical study of the influence of small angle scattering on diffraction enhanced imaging

Small angle scattering plays an important role in diffraction enhanced imaging (DEI). The DEI equation proposed by Chapman is accepted and widely used by many applications in medical, biological and material researches. However, in this framework the contribution of the small angle scattering determined by the crystal analyzer is neglected and the extinction contrast caused by the rejection of the small angle scattering by the analyzer is not explicitly expressed. In this contribution we introduce two additional terms in the DEI equation that describe the additional background introduced by the small angle scattering collected by the analyzer crystal and the extinction contrast associated to the rejection of the small angle scattering by the analyzer crystal, respectively. Four kinds of images of the DEI method were considered by using these revised equations and results were presented and discussed.     

Comparison of NAA and ICP-MS for the determination of major and trace elements in environmental sample

Summary Major and trace elements in soil and plant samples, including standard reference materials were determined by means of neutron activation analysis (NAA) and inductively coupled plasma-mass spectrometry (ICP-MS). The analytical procedure for NAA utilized dried powder samples. The concentration of iodine in soil samples was determined by radiochemical NAA. The irradiated samples were cooled and then counted with a Ge gamma-ray detector connected to a multi-channel analyzer. For ICP-MS analysis, the samples were decomposed by microwave digestion with an acid mixture. The concentration of I in the soil samples was measured by ICP-MS after separation by ignition. The analytical values for most elements in the environmental samples by both methods were in good agreement, whereas sample treatments were different. Measured value of Zr in the soil samples by ICP-MS was about 50% lower than that by NAA. It should be assumed that some minerals of Zr in soil particles were not entirely dissolved by the acid mixture. Analytical results of Cd for three different Cd levels in unpolished rice flour samples (NIES 10-a, b and c) determined by ICP-MS were in agreement with certified values. The concentration of Cd in the sample with the lowest Cd level, as determined by NAA with 57% counting error, was 3 times higher than the certified value.     

Radiation-induced polymerization of 2,3-dimethyl-1,3-butadiene clathrate in deoxycholic acid

Poly(dimethylbutadiene) (PDMB) was synthesized through the inclusion polymerization technique, by γ-irradiation of a clathrate of 2,3-dimethyl-1,3-butadiene in deoxycholic acid (DOCA) at 75, 150, 320 and 430 kGy. The resulting inclusion complexes PDMB@DOCA were studied by FTIR spectroscopy and by thermal analysis (DTA, TGA and DTG). Pure PDMB was isolated by extracting the complex PDMB@DOCA with ethanol. The best sample in terms of purity was that prepared at 75 kGy, while the other samples prepared at higher doses suffered of DOCA grafting on PDMB chains. Pure PDMB isolated from PDMB@DOCA complex was studied by FT-IR spectroscopy and by thermal analysis in comparison to a reference highly crystalline and ≈=100% trans-1,4-PDMB prepared by inclusion polymerization in thiourea and in comparison to PDMB prepared by emulsion polymerization. A lower degree of regularity and crystallinity has been found on the PDMB sample prepared as inclusion compound in DOCA in comparison to the reference PDMB obtained by inclusion polymerization in thiourea.     

方波伏安法评估聚苯胺膜修饰电极的电荷传输速度

研究导电聚合物的电荷传输机制与速度对于其在应用方面的研究极为重要［‘］．例如在电池的研究中，充放电的速度决定于导电聚合物的电荷传输速度；在电致变色器件的研究中，响应时间也是决定于导电聚合物在氧化还原态间的变化速度，即电荷传输速度．显然较低的电荷传输速度不利于器件的实用化，因此人们必须找到一种能够迅速准确评价电荷传输速度的方法，由于导电聚合物是一个特殊的体系，用一般的电化学方法对其电荷传输速度进行测定时常常遇到这样或那样的问题［‘j．一般说来，导电聚合物的氧化还原过程中均伴随着抗衡离子的运动．体系…     

Comparative determination of uranium in rock phosphates and columbite by ICP-OES,alpha &; gamma spectrometry

During this work selective separation of uranium from rock phosphate and columbite mineral was done before its quantitative estimation by using Inductively Coupled Plasma Optical Emission Spectrometery (ICP-OES). Uranium from the rock phosphate and columubite was extracted by sodium peroxide fusion followed by leaching in 2 M HNO₃. To avoid spectral interference in the estimation of uranium by ICP-OES, the selective separation of uranium from the leachate was carried out by using two different extractants, 30% Tributyl Phophates (TBP) in CCl₄ and a equi-volume mixture of Di(2-ethylhexyl) phosphoric acid (D2EHPA) & TBP in petrofin. Uranium was stripped from the organic phase by using 1 M ammonium carbonate solution. Determination of uranium by ICP-OES was done after dissolving the residue left after evaporation of ammonium carbonate solution in 4% HNO₃. The concentration of the uranium observed in the rock phosphates samples was 40–200 μg g⁻¹ whereas in columbite samples the concentration range was 100–600 μg g⁻¹. Uranium concentration evaluated by ICP-OES was complimented by gamma & alpha spectrometry. Concentration of uranium evaluated by gamma spectrometry in case of rock phosphate and coulmbite was in close agreement with the uranium content obtained by ICP-OES. Uranium determination by alpha spectrometry showed only minor deviation (1–2%) from the results obtained by ICP-OES in case of rock phosphates whereas in case of coulmbites results are off by 20–30%.     

β-沸石骨架铝化改性的红外光谱

β沸石是以有机胺为模板剂合成的高硅沸石．为在孔道中进行吸附和催化反应,通常是在空气中 (５５０℃ )进行焙烧,将有机胺脱除并使质子酸中心形成．但这种脱模板剂方法,会造成骨架脱铝［１ -４］,使质子酸中心显著减少．β沸石固有结构中存在着孔道位错和结构空穴,空气中焙烧脱有机胺可能会进一步损伤沸石的骨架结构［４,５］．沸石骨架改性已发展了多种铝化方法［６ -８］．有的研究工作表明,通常用红外光谱和ＭＡＳＮＭＲ表征的非骨架铝,在温和的条件下,例如回馏温度下的离子交换或者在较低温度下 (１００℃或室温 )与碱反应就可…     

Proteomic identification of exosomal LRG1: a potential urinary biomarker for detecting NSCLC

In the present research, we aimed to screen for non-small cell lung cancer (NSCLC)-related proteins in urinary exosomes by comparing urinary exosomes proteome of normal controls and NSCLC patients. Urinary exosomes were isolated by ultracentrifugation and identified by electron microscopy. Exosomal proteins were separated by 1-D SDS-PAGE and the differentially expressed bands between healthy controls and NSCLC patients ranging in size from 35 to 45?kD were cut from the gel. After tryptic digestion, 18 proteins were identified by nano-HPLC-chip-MS/MS. The differential expression of leucine-rich α-2-glycoprotein (LRG1) was further validated in urinary exosomes by Western blot and in lung tissue by immunohistochemistry. The LRG1 was found to be expressed at higher levels in urinary exosomes and lung tissue of NSCLC patients. These results suggested that LRG1 may be a candidate biomarker for non-invasive diagnosis of NSCLC in urine.