Chemiluminescence sensor for isoniazid with controlled-reagent-release technology

A novel chemiluminescence (CL) sensor for isoniazid combined with flow-injection technology is presented in this paper. The analytical reagents, luminol and ferricyanide, were both immobilized on an anion-exchange column. The CL signal produced by the reaction between luminol and ferricyanide, which were eluted from the column through sodium phosphate injection, was decreased in the presence of isoniazid. The decreased CL intensity was linear with isoniazid concentration in the range 0.001–1.0 μg·ml⁻¹; and the detection limit was 0.35 ng·ml⁻¹ (3s). The whole process, including sampling and washing, could be completed in 2 min with a relative standard deviation of less than 4.1%. The sensor could be reused more than 400 times and has been applied for the determination of isoniazid in pharmaceutical preparations.     

Crystallization behavior and biodegradation of poly(3-hydroxybutyrate) and poly(ethylene glycol) multiblock copolymers

Block copolymerization by using isocyanates is an effective method for incorporating PHB and PEG because it can prepare copolymers with good properties, such as toughness, strength, and so on. In this study, we adopted soil suspension system to estimate the biodegradability of a series of PHB/PEG multiblock copolymers with different compositions and block lengths. In the degradation process, the changes in weight loss, molecular weight, and tensile strength were periodically measured to determine the biodegradability, and the surface morphology was also observed by SEM. In contrast to pure PHB, the weight loss of the copolymer was relatively lower. On the other hand, the tensile strength and molecular weight experienced apparent decrease, and for BHG1000-3-1, they reached 46.7% and 77.7% of the initial value, respectively. SEM observation showed that the surface was covered with numerous erosion pits. All these indicate that the degradation indeed took place and long-chain molecules have been hydrolyzed into shorter ones. The crystallization behavior was also investigated by DSC and WAXD. The results showed that both the segments, PEG and PHB, can form crystalline phases at lower PHB contents ranging from 29% to 44%, and when PHB component was more than 60%, only PHB phase can crystallize.     

Pt-Sn脱氢催化剂浸渍状态的Sn-119和Pt-195的多核NMR研究

测定了Ｐｔ－Ｓｎ型催化剂浸渍状态下的Ｓｎ－１１９、Ｐｔ－１９５的多核核磁共振。当ＳｎＣｌ２／ＤＣｌ溶液体系中加入Ｈ２ＰｔＣｌ６以后，出现了Ｓｎ（Ⅳ）和另外一种Ｓｎ（Ⅱ）的构型，Ｓｎ－１１９峰向高场位移，说明部分Ｓｎ（Ⅱ）被氧化成Ｓｎ（Ⅳ），Ｈ２ＰｔＣｌ６的量对这种氧化性影响较小。而Ｈ２ＰｔＣｌ６／Ｄ２Ｏ溶液体系中加入ＳｎＣｌ２以后部分Ｐｔ（Ⅳ）被还原成Ｐｔ（Ⅱ），随着ＳｎＣｌ２量的增加，Ｐｔ（Ⅱ）     

Application of an integrated microchip system with capillary array electrophoresis to optimization of enzymatic reactions

In this work, a combination of complementary metal-oxide semiconductor (CMOS) microchip system with capillary array electrophoresis (CAE) is demonstrated as a system for optimizing conditions for enzymatic reaction. Dimethylacridinone (DDAO)-phosphate substrate and alkaline phosphatase conjugate were selected for the enzymatic reaction, which was applicable to the enzyme-linked immunosorbent assay (ELISA) technique. Laser-induced fluorometry with a miniature semiconductor laser was used to detect the enzymatic products. The speed of the enzymatic reaction between the DDAO-phosphate and the alkaline phosphatase conjugate was investigated as a function of reaction time. The microchip-CAE detection system could determine the pH condition and the concentration of enzyme that are suitable for rapid and low-cost analysis. This result shows the feasibility of using the microchip-CAE system for application to miniaturized screening systems.     

Electrospray ionization tandem mass spectrometric study of the aconitines in the roots of aconite

Fragmentation pathways of aconitine-type alkaloids were investigated by electrospray ionization/ion trap multistage tandem mass spectrometry. Low-energy collision-induced dissociation of protonated aconitines follows a dominant first step, the elimination of the C(8)-substituent as acetic acid or fatty acid in MS(2) spectra. Successive losses of 1-4 CH(3)OH molecules, 1-3 H(2)O, CO, benzoic acid, and CH(3) or C(2)H(5) (N-substituents) are all fragmentation pathways observed in MS(3) and MS(4) spectra. By applying knowledge of these fragmentation pathways to the aconitines in the ethanolic extract of aconite roots, all the known aconitines were detected and also 23 unknown aconitine-type alkaloids, in which the lipo-alkaloids containing residues of 15C, 17C and 19C saturated or unsaturated fatty acids were characterized. These odd-carbon-number fatty acid substituents have not been reported previously.     

Trajectory studies of S(N)2 nucleophilic substitution. 8. Central barrier dynamics for gas phase Cl(-) + CH(3)Cl

Quasiclassical direct dynamics trajectories, calculated at the MP2/6-31G level of theory, are used to study the central barrier dynamics for the C1(-) + CH(3)Cl S(N)2 reaction. Extensive recrossings of the central barrier are observed in the trajectories. The dynamics of the Cl(-)-CH(3)Cl complex is non-RRKM and transition state theory (TST) is predicted to be an inaccurate model for calculating the Cl(-) + CH(3)Cl S(N)2 rate constant. Direct dynamics trajectories also show that Cl(-) + CH(3)Cl trajectories, which collide backside along the S(N)2 reaction path, do not form the Cl(-)-CH(3)Cl complex. This arises from weak coupling between the Cl(-)-CH(3)Cl intermolecular and CH(3)Cl intramolecular modes. The trajectory results are very similar to those of a previous trajectory study, based on a HF/6-31G* analytic potential energy function, which gives a less accurate representation of the central barrier region of the Cl(-) + CH(3)Cl reaction than does the MP2/6-31G* level of theory used here. Experiments are suggested for investigating the non-RRKM and non-TST dynamics predicted by the trajectories.     

Clinical significance of molecular genetic changes in sporadic invasive pituitary adenomas

Several molecular and genetic changes have been found in pituitary adenomas. We looked for correlations between these changes and the degree of invasiveness of the tumors. The invasiveness of 11 pituitary adenomas was graded by Hardy classification. We examined the retinoblastoma gene (RB1.20 on chromosome 13q) and the region around the MEN1 locus (chromosome 11q13.1-5) for loss of heterozygosity. Also examined are p53 mutations using single strain conformation polymorphism, p53 protein overexpression using immuno cytochemistry, homozygous deletions of p15 and p16 by polymerase chain reaction, and cellular proliferative activity using MIB-1 antibody. Six tumors (54.5%) had an LOH at either RB1.20 or the MEN1 locus. LOHs were found more frequently in Grade 4 and stage E tumors (72% and 67%) than in Grade 3 and stage D tumors (25% and 40%). However, no mutation or overexpression of p53 was found. No homozygous deletions of p15 or p16 were identified. The cell proliferative index ranged from 0 to 3%. LOH at 11q13 and 13q may be valuable in predicting the invasiveness of pituitary adenomas.     

Miniature biochip system for detection of Escherichia coli O157:H7 based on antibody-immobilized capillary reactors and enzyme-linked immunosorbent assay

In this work, we report Escherichia coli O157:H7 detection using antibody-immobilized capillary reactors, enzyme-linked immunosorbent assay (ELISA), and a biochip system. ELISA selective immunological method to detect pathogenic bacteria. ELISA is also directly adaptable to a miniature biochip system that utilizes conventional sample platforms such as polymer membranes and glass. The antibody-immobilized capillary reactor is a very attractive sample platform for ELISA because of its low cost, compactness, reuse, and ease of regeneration. Moreover, an array of capillary reactors can provide high-throughput ELISA. In this report, we describe the use of an array of antibody-immobilized capillary reactors for multiplex detection of E. coli O157:H7 in our miniature biochip system. Side-entry laser beam irradiation to an array of capillary reactors contributes significantly to miniaturized optical configuration for this biochip system. The detection limits of E. coli O157:H7 using the ELISA and Cy5 label-based immunoassays were determined to be 3 and 230 cells, respectively. This system shows capability to simultaneously monitor multifunctional immunoassay and high sensitive detection of E. coli O157:H7.     

Hetero-calix[4]pyrroles: incorporation of furans, thiophenes, thiazoles or fluorenes as a part of the macrocycle

Furans, thiazoles, fluorene or thiophene incorporated calix[4]pyrrole analogues were synthesized and characterized. The synthesis was achieved by utilization of various building blocks such as 7, 13, 14, 18 and 21. Acid catalyzed condensation of those building blocks with acetone or meso-disubstituted dipyrromethanes afforded desired macrocycles.     

Molecular variations in Th1-specific cell surface gene Tim-3

The family of T-cell immunoglobulin domain and mucin domain (TIM) proteins is identified to be expressed on T cells. A member of Tim family, Tim-3 (T cell immunoglobulin mucin 3) is selectively expressed on the surface of differentiated Th1 cells. Tim-3 might have an important role in the induction of autoimmune diseases by regulating macrophage activation and interacts with Tim-3 ligand to regulate Th1 responses. To determine the variation sites in the coding and promoter region of human Tim-3 gene, we performed variation scanning by direct sequencing using the genomic DNA isolated from the patients with asthma or allergic rhinitis and healthy controls without asthma and allergic rhinitis. We identified four single nucleotide polymorphisms (SNPs) including one novel SNPs (-1541C>T) and two variation sites (-1292_-1289delTAAA and -1282_-1278dupTAAAA) in the coding and promoter region of human Tim-3 gene in both the patients and healthy groups.