The possibility of graded-index plastic optical fibers containing lanthanide chelates for amplifiers and lasers

Absorption spectra of lanthanide ions in perfluorinated (PF) plastic solution were measured, and Judd-Ofelt parameters (Ω₂, Ω₄, Ω₆) were determined by the absorption measurements. Fluorescence spectrum of Nd³⁺ in PF plastic solution from 900 nm to 1350 nm, pumped at 580 nm, were measured for the first time.     

Genetic diagnosis by polymerase chain reaction and electrospray ionization mass spectrometry: Detection of five base deletion from blood DNA of a familial adenomatous polyposis patient

A 5-base deleted mutation of adenomatous polyposis coli (APC) gene was detected by using electrospray ionization mass spectrometry of polymerase chain reaction (PCR) products. Genomic DNA was extracted from a familial adenomatous polyposis patient blood, and a 57-base pairs segment of APC gene was amplified by PCR. The PCR products were purified, digested with restriction endonuclease, purified, and determined by electrospray mass spectrometry.     

Synthesis and optical properties of polyimides

Polyimides are important industrial materials because of their excellent properties. They are extensively used in the electronics industry and have great potential in the field of optical communications. In this article, we discuss the effect of the polyimide structure and the processing conditions on the optical properties. Both commercially available fluorinated polyimides and polyimides synthesized in our laboratory were used in this study. The relationship between the extent of fluorination and the refractive index was studied, and it was found that fluorination reduced the refractive index as expected. Studies conducted on the structure–property relationship revealed that with the use of more rigid monomers for the polyimides, the polyimides could be modified to show a large birefringence. The extent of birefringence depended on the composition of the polymer. In addition, the processing conditions directly controlled the residual stress in the polymer films. The residual stress was an important factor in inducing light scattering, which resulted in higher optical loss. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4832–4838, 2000     

Theoretical Consideration of the External Donor of Heterogeneous Ziegler–Natta Catalysts Using Molecular Mechanics,Molecular Dynamics,and QSAR Analysis

In the previous paper we calculated the most stable structure of the catalyst and cocatalyst of metallocene catalyst systems using molecular dynamics and molecular mechanics. In this paper we postulate the active site of the heterogeneous Ziegler–Natta catalyst, and analyze it by the same methods to clarify the main factors that control the activity and molecular weight distribution of the heterogeneous catalyst systems. The roles of the external donor were also considered, and we found that the interaction energy between an external donor and the active site of the catalyst, as well as the structural factors of the external donor itself, are strongly related to both activity and molecular weight distribution. These results reveal that molecular dynamics and molecular mechanics calculations are also effective methods to screen the heterogeneous catalyst systems.     

Peptoid-based reprogrammable template for cell-permeable inhibitors of protein–protein interactions

The development of inhibitors of intracellular protein–protein interactions (PPIs) is of great significance for drug discovery, but the generation of a cell-permeable molecule with high affinity to protein is challenging. Oligo(N-substituted glycines) (oligo-NSGs), referred to as peptoids, are attractive as potential intracellular PPI inhibitors owing to their high membrane permeability. However, their intrinsically flexible backbones make the rational design of inhibitors difficult. Here, we propose a peptoid-based rational approach to develop cell-permeable PPI inhibitors using oligo(N-substituted alanines) (oligo-NSAs). The rigid structures of oligo-NSAs enable independent optimization of each N-substituent to improve binding affinity and membrane permeability, while preserving the backbone shape. A molecule with optimized N-substituents inhibited a target PPI in cells, which demonstrated the utility of oligo-NSA as a reprogrammable template to develop intracellular PPI inhibitors.

A peptoid-based modular approach using oligo(N-substituted alanine) as a reprogrammable template enables independent optimization of N-substituents and facile development of cell-permeable inhibitors of protein–protein interactions.