Association of europium(III), americium(III), and curium(III) with cellulose, chitin, and chitosan

The association of trivalent f-elements-Eu(III), Am(III), and Cm(III)--with cellulose, chitin, and chitosan was determined by batch experiments and time-resolved, laser-induced fluorescence spectroscopy (TRLFS). The properties of these biopolymers as an adsorbent were characterized based on speciation calculation of Eu(III). The adsorption study showed that an increase of the ionic strength by NaCl did not affect the adsorption kinetics of Eu(III), Am(III), and Cm(III) for all the biopolymers, but the addition of Na2CO3 significantly delayed the kinetics because of their trivalent f-element complexation with carbonate ions. It also was suggested from the speciation calculation study that all the biopolymers were degraded under alkaline conditions, leading to their masking of the adsorption of Eu(III), Am(III), and Cm(III) on the nondegraded biopolymers. The masking effect was higher for cellulose than for chitin and chitosan, indicating that of the three, cellulose was degraded most significantly in alkaline solutions. Desorption experiments suggested that some portion of the adsorbed Eu(III) penetrated deep into the matrix, being isolated in a cavity-like site. The TRLFS study showed that the coordination environment of Eu(III) is stabilized mainly by the inner spherical coordination in chitin and by the outer spherical coordination in chitosan, with less association in cellulose in comparison to chitin and chitosan. These results suggest that the association of these biopolymers with Eu(III), Am(III), and Cm(III) is governed not only by the affinity of the functional groups alone but also by other factors, such as the macromolecular steric effect. The association of degraded materials of the biopolymers also should be taken into consideration for an accurate prediction of the influence of biopolymers on the migration behavior of trivalent f-elements.     

Subcellular location of horseradish peroxidase in horseradish leaves treated with La(III), Ce(III) and Tb(III)

The agricultural application of rare-earth elements (REEs) would promote REEs inevitably to enter in the environment and then to threaten the environmental safety and human health. Therefore, the distribution of the REEs ion, ¹⁴¹Ce(III) and effects of La(III), Ce(III) and Tb(III) on the distribution of horseradish peroxidase (HRP) in horseradish mesophyll cells were investigated with electron microscopic radioautography and transmission electron microscopic cytochemistry. It was found for the first time that REEs ions can enter into the mesophyll cells, deposit in both extra and intra-cellular. Compared to the normal condition, after the horseradish leaves treated with La(III) or Tb(III), HRP located on the tonoplast is decreased and HRP is mainly located on the cell wall, while HRP is mainly located on the plasma membrane after the horseradish leaves were treated with Ce(III). This also indicated that REEs ions may regulate the plant growth through changing the distribution of enzymes.     

Synthesis and spectroscopic studies of biologically active compounds derived from oxalyldihydrazide and benzil, and their Cr(III), Fe(III) and Mn(III) complexes

A new series of complexes have been synthesized by template condensation of oxalyldihydrazide and benzil in methanolic medium in the presence of trivalent chromium, manganese and iron salts forming complexes of the type [M(C(32)H(24)N(8)O(4))X]X(2) where M = Cr(III), Mn(III), Fe(III) and X = Cl(-1), NO(3)(-1), CH(3)COO(-1). The complexes have been characterized with the help of elemental analyses, conductance measurements, magnetic susceptibility measurements, electronic, NMR, infrared and far infrared spectral studies. On the basis of these studies, a five coordinate square pyramidal geometry has been proposed for all these complexes. The biological activities of the metal complexes have been tested in vitro against a number of pathogenic bacteria to assess their inhibiting potential. Some of these complexes have been found to exhibit remarkable antibacterial activities.     

Sorption of Phosphate and Cr(VI) by Fe(III) and Cr(III) Hydroxides

Understanding the chemical behavior and interactions of Cr(VI) (e.g., HCrO₄ ⁻) and other anions, such as orthophosphate (P) with insoluble metal hydroxides (i.e., Cr[III] and Fe[III]) in disposal landfills or in chromite ore processing residue (CORP)–enriched soil is very important in predicting the movement and the fate of Cr(VI). This study evaluates the sorption behavior of P and Cr(VI) by Fe(III) (i.e., ferrihydrite), Cr(III) (i.e., Cr[OH]₃), and coprecipitated Fe(III)/Cr(III) hydroxides. These metal hydroxide sorbents were synthesized, and sorption of P and Cr(VI) were conducted at different pH using a batch technology. Our results show that P and Cr(VI) sorption by metal hydroxides decreased with increasing suspension pH. Greater decrease in P sorption was observed when Cr(III) was present in the structures of hydroxides. Following the sorption of low concentration of P (i.e., 0.5 mM), the sorption of subsequently added Cr(VI) by hydroxides was less influenced. However, Cr(VI) sorption was greatly inhibited when high concentration of P (i.e., 10 mM) prereacted with hydroxides, particularly in Fe(III) hydroxide system. Results also indicated that high concentration of Cr(VI) (10 mM) could dissolve Cr(III) hydroxide at pH 3 and reprecipitate as an amorphous form of Cr(VI) and Cr(III) compound at pH about 6.5. Although coprecipitation of Cr(VI) with Cr(III) can inhibit Cr(VI) movement through soil profiles, the inhibition seems to be low due to the gradual release of Cr(VI) with increasing pH. Received: 16 April 2002/Accepted: 29 October 2002     

深圳市小学生口腔保健知识、态度、行为调查

目的　了解深圳市小学生口腔保健知识、态度、行为 (KAP)的现况及患龋情况 ,分析与学生龋齿有关的口腔保健KAP因素 ,为今后制定口腔防治、干预措施 ,有针对性地开展健康教育提供依据。方法　采用整群抽样方法抽取深圳市布心小学 1878名在校学生 ,进行龋齿患病情况检查和口腔保健KAP问卷调查。结果　学生龋齿患病率 6 4 70 % ,学生口腔保健知识、行为得分较低 ,与学生患龋有关的因素主要是口腔保健行为的形成率、知识的知晓率对龋齿的影响较小。结论　深入开展口腔健康教育 ,不仅要增强口腔保健知识和信念 ,还应采取必要的干预措施提高学生口腔保健行为的形成率 ,改善口腔卫生状况 ,降低患龋率     

Association mechanisms of Europium(III) and Curium(III) with Chlorella vulgaris

The association of Europium(III) (Eu[III]) and Curium(III) (Cm[III]) with Chlorella vulgaris and with cellulose was studied by a batch method and time-resolved laser-induced fluorescence spectroscopy (TRLFS). The kinetics study performed by the batch method showed that maximum adsorption of Eu(III) and Cm(III) on C. vulgaris was attained within 3 min of contact; afterward, the percentage adsorption decreased with time due to chelation of the ions with exudates released from C. vulgaris with a strong affinity for Eu(III) and Cm(III). The TRLFS revealed that the short-term adsorption of Eu(III) on C. vulgaris was attributable to its coordination with cellulose on the algal cell wall. However, Eu(III) coordinated with the functional groups of cellulose very weakly despite the large distribution coefficients observed. These results indicate that the reactions, both at the cell's surfaces through adsorption and in solution phases through chelation with the exudates, are important in estimating the behavior of Eu(III) and Cm(III) in aqueous environments.     

Co(III), Ni(II), Zn(II) and Cd(II) complexes with 2-acetyl-2-thiazoline thiosemicarbazone: Synthesis, characterization, X-ray structures and antibacterial activity

The new ligand 2-acetyl-2-thiazoline thiosemicarbazone (HATtsc) and the complexes [Co(ATtsc)₂]₂[CoCl₄]·2H₂O (1), [Co(ATtsc)₂]NO₃·H₂O (2), [Ni(HATtsc)₂](NO₃)₂ (3), [ZnCl₂(HATtsc)]·CH₃CN (4), [{CdCl(HATtsc)}₂(μ-Cl)₂]·2H₂O (5) and [{Cd(NO₃)(HATtsc)}₂(μ-NO₃)₂] (6) were isolated and characterized by a variety of physico-chemical techniques and X-ray diffraction. The structure of HATtsc in 1 and 2 presented a thiolate form while in 3-6 the thione form was present, as it was in free ligand. In addition, we studied the antibacterial activity of the ligand and complexes 2-6 against some representative bacteria. Cd(II) complexes were more active against Staphylococcus epidermidis, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Bacillus subtilis than organic ligand. Conversely, Cd(II) compounds seemed to interfere in the cell separation of B. subtilis.     

Significance of organic crops in health prevention illustrated by the example of organic paprika (Capsicumannuum)

The paprika fruits are perfect source of bioactive compounds as carotenoids (beta-carotene and lutein), flavonoids and vitamin C. The aim of work was to determine the content of bioactive compounds in paprika fruits from organic and conventional cultivation. Organic and conventional paprika fruits were chemically analyzed. The results obtained showed that organic paprika contained more total and reducing sugars, vitamin C and flavonoids than conventional one. Additionally organic paprika fruits had slightly higher acidity than conventional fruits.     

Function and disability or quality of life? Issues illustrated by the Osteoporosis Functional Disability Questionnaire (OFDQ)

There continues to be a lack of consensus on the meaning and definition of the concept of quality of life. An implicit distinction for many measures of quality of life is from measures of health status based upon the presence of disability in functional domains. A further assumption in many scales is that quality of life is a unitary construct. The Osteoporosis Functional Disability Questionnaire (OFDQ) assessed some domains of function but is not unidimensional. It was developed to evaluate the progress and outcome of a structured exercise program for people with spinal compression fractures due to osteoporosis. The OFDQ assesses five domains relevant to the pain and disability in this population: pain, depression, function in performing common daily activities, socialization, and confidence in the exercise program. Longitudinal data from three cases are used to illustrate the utility of this multidimensional approach in evaluating the outcome of exercise treatment and understanding important aspects of the subjective life of people with osteoporosis.     

荧光定量PCR技术在解脲支原体(UU),沙眼衣原体(CT),淋病球菌(NGH)基因检测结果分析

目的:用荧光定量PCR技术(FQ-PCR)检测解脲支原体(Uu),沙眼衣原体(CT),淋病球菌(NGH)基因,进一步了解Uu,CT,NGH的感染情况,为临床治疗提供依据。方法:采用FQ-PCR技术检测疑为泌尿生殖道感染患者分泌物标本457份。结果:Uu阳性率43.3%,其中女性Uu阳性率60.8%,男性Uu阳性率32.4%。CT阳性率15.9%,NGH阳性率12.6%,Uu在男女间差异有统计学意义,而CT,NGH无统计学意义。结论:荧光定量PCR检测UuCT NGH基因具有操作简便、反应时间短、重复性好、结果客观准确、敏感性和特异性好等优点,其结果对临床诊断、治疗有一定的指导意义。