PHOTO ACOUSTIC SPECTRA OF PHYCOBILIPROTEINS and CHLOROPHYLLIN IN ISOTROPIC and ANISOTROPIC POLYVINYL ALCOHOL FILMS

Abstract— Photoacoustic spectra (PAS) of biliproteins: R-phycoerythrin (PE) with R-phycocyanin (PC) admixture in isotropic and anisotropic polyvinyl-alcohol (PVA) films were measured. The mixtures of biliproteins and chlorophyllin (Chllin) in PVA were also investigated. In order to establish the influence of PVA anisotropy on PAS amplitude, the stretched and unstretched PVA films colored by Congo red were studied. The films with PE and Chllin mixture when illuminated in the region of PE absorption, show higher PAS signals than the films with PE alone. This is explained by the excitation energy transfer from efficiently fluorescent PE to Chllin that has much lower yield of fluorescence. The stretched films always show a higher PAS signal than isotropic films because of the increase in the thermal conductivity of PVA. But normalized PAS of Congo red and Chllin in stretched PVA are similar to those in unstretched films.
Pigment molecules oriented parallel to the direction of film stretching have a lower rate of thermal deactivation compared to that of unoriented molecules as has been found by comparing PAS of differently oriented Congo red molecules using photoselection by polarized light. The same result was obtained for various PE chromophores which are differently oriented in anisotropic films.     

POLARIZED TIME-RESOLVED FLUORESCENCE SPECTRA OF PHYCOBILISOMES ISOLATED FROM Tolypothrix tenuis EMBEDDED IN POLY(VINYL ALCOHOL) FILM

–Time-resolved fluorescence spectra in the ps time range were measured on phycobilisome (PBS) embedded in poly(vinyl alcohol) films. The cyanobacterium Tolypothrix tenuis was used as a source of PBS because the pigment composition and the structure of the PBS are well defined. Isotropic PBS in the unstretched film and PBS uniaxially oriented in the stretched film were investigated. Diameters of PBS hemidiscs were oriented parallel to the film-stretching direction. The time-resolved fluorescence spectra of the unstretched sample and of the two polarized components in the stretched samples showed several differences in the rise and decay. The delay time, estimated from the time span between the maximum laser pulse and maximal intensity of the phycocyanin and allophycocyanin fluorescence, was much longer than that reported in the aqueous media. This suggests occurrence of a higher thermal deactivation of PBS in polymer film than in aqueous media. The excitation energy transfer from excited phycocrythrin to allophycocyanin was more efficient in the unstretched than in the stretched samples, and it was greater in the parallel polarized component of the stretched sample than in the perpendicular component. The present results are in agreement with a previous suggestion which states that there are two independent pathways of excitation energy transfer in PBS and that there is more than one final emitter of fluorescence. The molecules taking part in various pathways of energy transfer differ in their orientation within PBS.     

POLARIZED PHOTOACOUSTIC SPECTRA OF PHYCOERYTHRIN and PHYCOCYANIN IN ANISOTROPIC POLYMER FILMS

Abstract— Photoacoustic spectra (PAS) of biliproteins, namely, R-phycoerythrin (PE) and C-phycocyanin (PC) and their mixture in anisotropic and isotropic polyvinylalcohol (PVA) films were measured under the illumination with polarized and natural light. Also samples in deuterated PVA were investigated. The yields of fluorescence of various chromophores of investigated biliproteins were obtained from PAS, absorption, fluorescence and fluorescence lifetime measurements. The deuteration of samples causes different changes in thermal deactivation of excitation of various chromophores. Ratios of PAS to absorption of the light polarized parallel and perpendicular to the direction of film stretching are different. The PAS amplitude of deuterated samples is higher than that for undeuterated.     

聚乙烯醇纤维金属配合物的合成和表征

以聚乙烯醇纤维(PVA)为配体原料,分别与FeCl3、NiCl2、CuCl2和Pb(Ac)2反应,制备了宏观上仍保持原纤维形态的PVA Fe(Ⅲ)、PVA Ni(Ⅱ)、PVA Cu(Ⅱ)、PVA Pb(Ⅱ)纤维配合物(用PVA M表示).用红外光谱仪分别对PVA和4种配合物在4000～400cm-1范围进行傅立叶变换红外光谱测量,对各PVA M的FTIR主要吸收峰做了经验归属,并与PVA的相应吸收峰做对比分析,结果表明,与金属离子形成配合物后,PVA分子中O—H氢键缔合状态被破坏,向高波数位移了65～86cm-1,PVA中的羟基氧与金属离子发生配位作用.PVA Fe(Ⅲ)的XPS显示,PVA中O1s只出现532.5eV单峰,而PVA Fe(Ⅲ)中O1s分裂为531.4eV和532.3eV两个峰,且Fe2p只有一个峰710.9eV,比FeCl3的结合能值711.2eV下降,说明OH氧与Fe3+形成配位键.     

聚乙烯醇的强化辐射交联

通常γ-辐照裂解的聚乙烯醇(PVA)在N·N’-甲基丙烯酰胺(BAM)存在下可以辐射交联。BAM/PVA体系的辐射效应可大致依辐照剂量的增加划分为三个阶段:强化辐射交联为主区,强化辐射交联与辐射裂解相抵区和辐射裂解优势区。强化辐射交联区的溶胶分数S与辐照剂量D的关系可表示为: S=(1 (1/(1-K))D_g~(2=K))-(D_g/(1-K))D~(1-K) =A-BR~(1-K)式中,D_g为凝胶化剂量;K是与BAM含量相关的常数。     

POLARIZED OPTICAL PROPERTIES OF PHYCOBILISOMES FROM Anabaena, Nostoc and Synechococcus

Polarized absorption, photoacoustic, fluorescence excitation and fluorescence emission spectra of phycobilisomes were measured when embedded in polyvinyl alcohol films. The phycobilisomes were isolated from the following organisms: Anabaena cylindrica, Nostoc punctiforma and Synechococcus elongatus. The ratio of photoacoustic spectra to absorption was taken as a measure of thermal dissipation of excitation energy. The isotropic samples and those oriented by the film stretching were investigated. The stretching of the sample strongly influences the efficiency of excitation energy transfer occurring among biliproteins in phycobilisomes, as is seen from the dramatic changes in the fluorescence and thermal dissipation spectra. The effect of stretching the film depends on the shape of phycobilisomes and on the strength of interactions between biliproteins in phycobilisomes.     

含牛磺酸交联聚乙烯醇的合成及其对甘油三脂吸附性能*

以牛磺酸修饰交联聚乙烯醇凝胶合成了吸附剂。吸附实验结果表明：该类吸附剂对血清中甘油三脂具有良好的吸附效果,而对血清中总蛋白的吸附性能相对较弱。它们对甘油三脂的吸附性能着吸附剂上功能基含量的增加而加强,但随着载体的交联度的提高而降低。血清中致病因子的浓度影响吸附性能。     

聚乙烯醇磷酸酯水凝胶电刺激响应行为的研究

以脲为催化剂,将聚乙烯醇(PVA)磷酸酯化制成聚乙烯醇磷酸酯,再经戊二醛交联制备了一种新型的聚乙烯醇磷酸酯水凝胶.研究了水凝胶的溶胀性能,力学性能和电刺激响应行为.结果表明,该凝胶在NaCl水溶液中其平衡溶胀率随NaCl溶液的离子强度增大而减小.在离子强度为0~0.2的NaCl水溶液中,其弹性模量为0.300~0.356 MPa,抗张强度为91.5~137.8 kPa,断裂伸长率为32.0%~37.5%,且均随离子强度的增大而增大.在去离子水和NaCl水溶液中于非接触直流电场作用下,凝胶向电场负极弯曲,弯曲速度和应变随外加电压的增大而增大,并随NaCl离子强度的增大于0.005处出现极大值.在循环电场作用下,聚乙烯醇磷酸酯水凝胶的电刺激响应行为具有良好的可逆性.     

聚乙烯醇与硬脂酸酯化反应及性能的研究

聚乙烯醇 (ＰＶＡ)具有良好的成纤成膜性能 ,膜的阻氧性、透明性、抗静电性、韧性、印刷性和耐化学性能优异 ,用途广泛 .ＰＶＡ的缺点是吸湿性大 ,耐水性差 ,熔融加工困难和热稳定性低 .吸湿后 ,ＰＶＡ的强度仅为其干强度的 55%～ 60 % ,膜的阻氧性下降 .ＰＶＡ在 1 60℃开始分子内脱水 ,2 30℃时开始分子间脱水变脆 .由于分子内和分子间有大量氢键存在 ,ＰＶＡ熔融温度高 ,不能熔融加工 ,而溶液成型工艺复杂、成本高、难于制备厚壁和形状复杂的制品 .降低熔融温度、提高热稳定性能是实现ＰＶＡ熔融加工成型的必要条件 .国内外在采用马来酸…     

聚乙烯醇缩对甲酰基偶氮胂的合成及性质

首次研究了聚乙烯醇缩对甲酰基偶氮胂(PV-pFASA)的合成、纯化及其鉴定方法.并初步探讨了在光度分析和非有机溶剂革取分离方面的应用.结果表明,小分子显色剂高分子化后.其分析性能有了明显改善,特别是显色灵敏度和萃取率均有不同程度的提高.     

聚乙烯醇与苯乙烯的辐射接枝共聚

本文研究了若干因素对聚乙烯醇与苯乙烯辐射接枝共聚反应的影响,并对接枝产品的性能作了初步鉴定。 在体系里加入适量的水,接枝即甚易发生,此后接枝率先随着聚合物膜片的水含量而急剧增加,然后趋于平坦,而均聚反应速度增加较慢,且在较低的水含量时就不再上升。研究了剂率对接枝过程的影响,发现在常温当所用剂率大于100伦/分时,接枝反应完全受单体扩散控制,此时,接枝速率与剂率的依赖关系式V=KI~n中的n值趋近于零。 在10～80℃范围内,接枝与温度关系的曲线在60℃通过一极大值,然后下降。但均聚反应在整个温度范围内一直随温度而不断地增加,并在温度高于60℃时出现自动加速现象,这大概是凝胶效应的缘故。氧的存在对接枝反应起抑制作用。发现适量氧或空气 的存在可以使均聚反应受到显著抑制,而接枝反应仅略为减慢。接枝产品在沸水或沸苯中的溶胀比与接枝量成线性关系,膜片的抗酸碱性能因接枝而有明显改善。     

POLARIZED UV-ABSORPTION SPECTRA OF RETINAL ISOMERS-I. MEASUREMENTS IN EXTREMELY THIN MONOCRYSTAL PLATELETS

Abstract Crystals of all- trans retinal and both different forms of 11- cis , 12-s- cis retinal were grown on quartz slides with faces (101), (001) and (101), respectively, forming thin platelets of less than 0.2 μm thickness. Polarized UV absorption spectra at room temperature were measured in the range from 20 to 43 × 10³ cm⁻¹ with a microscope-spectrophotometer. In this spectral range three diffuse absorption bands were observed for all crystal types at similar wave numbers. A main absorption band was found at 25–28 × 10³ cm⁻¹, and two further bands at 32–34 and 38–40 × 10³ cm⁻¹. In case of all- trans retinal the latter band is by far the weakest in this spectral range. Additionally, the crystal spectrum of all- trans retinal shows a shoulder at the low wavenumber side of the main band which cannot be resolved in the corresponding solution spectrum. In the crystal spectra of 11- cis , 12-s- cis retinal, however, only a strong dissymmetry is observed at this side of the main band.     

细菌视紫红质-聚乙烯醇薄膜M态衰减动力学研究

利用闪光光解法和紫外 可见光谱法研究了室温条件下,pH值的增加和干燥时间的延长对细菌视紫红质 (bR)-聚乙烯醇 (PVA)薄膜光循环过程中M态衰减动力学的影响。闪光光解动力学研究表明,M态的衰减随着 pH值的提高和干燥时间的延长而明显减慢,在pH =1 0和干燥时间为 72h的最佳制备条件下薄膜M态的衰减最为缓慢.紫外 可见光谱法表明,M态的衰减可持续 15min以上,比自然条件下M态的寿命提高约 4个数量级.本文还探讨了最佳制备条件下细菌视紫红质-聚乙烯醇薄膜长寿命M态形成的机理.     

STUDIES ON POLYVINYL ALCOHOL CARRIERS Ⅲ. ACTIVE AMIDES AND ESTERS DERIVED FROM POLYVINYL ALCOHOL AND THEIR APPLICATION IN AFFINITY CHROMATOGRAPHY

Polyvinyl alcohol carriers bearing active amide and active ester groups were prepared by acetaliza-tion of granular macro-reticular water-insolub1e PVA with glyoxylic acid or p-formylbenzoic acidand further activation reaction with benzotriazole or N-hydroxysuccinimide using DCCI as con-densation agent. The active amides or active esters obtained were easy to react with amines suchas n-butylamine or proteins under mild condition. Ovomucoid, an inhibitor of trypsin was immo-bilized on the above-obtained reactive PVA carrier to give effective affinity adsorbent for the separa-tion or purification of trypsin.     

SEMI-BATCH RECOVERY OF POLYVINYL ALCOHOL FROM AQUEOUS SOLUTION BY ULTRAFILTRATION

ABSTRACT

01Aug1997     

PHOTOREDUCTION OF CRYSTAL VIOLET IN SOLUTION AND IN POLY(VINYL ALCOHOL) FILMS

Abstract— The photolysis of crystal violet oxalate has been studied in aqueous and non-aqueous solutions and in films of poly(viny1 alcohol) at room temperature. Evidence has been obtained from electron-spin-resonance, absorption and fluorescence spectroscopy for the formation of the semireduced dye radical, tri-( p -dimethylaminophenyl)methyl, both in solution and in the solid state. Electron spin resonance and luminescence spectra of the radical produced by electrolytic reduction of the dye are also reported.     

细乳液聚合法合成高分子量聚乙烯醇的研究

采用十二烷基硫酸钠(SDS)为乳化剂、十六醇(CA)为难溶助剂,引发醋酸乙烯酯(VAc)进行细乳液聚合,以偶氮二异庚腈(ADMVN)为引发剂时,制得了平均聚合度达1.5×104~2.0×104聚醋酸乙烯酯(PVAc)和4.1×103~6.6×103的聚乙烯醇(PVA);以偶氮二脒基丙烷盐酸盐(AAPH)为引发剂时,制得了平均聚合度达1.5×104~2.0×104的PVAc和2.1×103~4.4×103的PVA.研究了引发剂浓度、温度、油水比对产物聚合度、转化率的影响,讨论了SDS∶CA摩尔比对PVAc微球粒径分布及其成粒机理的影响.当cCA∶cSDS=3∶1时得到的细乳液体系稳定性最好,以ADMVN和AAPH引发聚合时均为液滴成核为主,其中以ADMVN引发得到PVAc微球的粒度分布窄于AAPH.     

DETERMINATION OF THE IN VIVO ABSORPTION AND PHOTOSYNTHETIC PROPERTIES OF THE LICHEN Acarospora schleicheri USING PHOTO ACOUSTIC SPECTROSCOPY

Photoacoustic spectroscopy was used to determine the in vivo spectra of the stratified components of the lichen Acarospora schleicheri. There were three pigmented layers observed by the photoacoustic method: an absorption band associated with the pigment rhizocarpic acid, a bulk cytochrome absorption, and the absorption of the algal chloroplast. Due to the different absorption properties of these distinct layers, the photoacoustic technique was able to monitor the physical effect of hydration on the lichen. Hydration of the lichen reduced the scatter of the sample, increasing the effective incident light intensity within the sample. Hydration also resulted in an increase in the optical absorption coefficient of the algal layer, which was interpreted as a movement of the algal chloroplast in response to low light fluence and hydrated conditions. The photoacoustic technique was also used to monitor the relative photosynthetic activity of the algae within the lichen in a hydrated and dehydrated state. The photosynthetic assay could detect photosynthetic activity in the hydrated state but not in the dehydrated state. In addition, the photosynthetic response was found to be induced and repressed with light and dark periods respectively and its detection was limited at high frequencies by the damping of the thermal wave from the algal layer.     

聚乙烯醇—Cr^3＋树胶状物的形成

在12≤pH≤13的5%PVA中添加0.2g CrCl_3·6H_2O有灰蓝色树胶状物析出。XPS、ESR、IR和电泳等研究表明,PVA的部分羟基发生脱质子反应而提供配位基L~-该配位基能与Cr(Ⅲ)盐和NaOH生成的初生Cr(OH)_3·nH_2O的Cr~(3+)形成配位键,从而发生配位体与Cr~(3+)间的交联反应,生成Cr(Ⅲ)-PVA配位聚合物。该析出物具有顺磁性,溶于盐酸,从而可用以富集和回收Cr(Ⅲ)。