Synthesis and evaluation of cross-linked poly(acryloylmorpholine) supports for thin-layer gel permeation chromatography

A range of poly(acryloylmorpholine) gel networks have been synthesized by aqueous suspension polymerization of acryloylmorpholine and N,N'-methylene-diacrylamide in differing molar ratios and at different monomer dilutions. Thin-layer techniques and dyed protein standards were employed to evaluate the networks directly as matrices for aqueous gel permeation chromatography. Increase in the Wheaton and Baumann distribution coefficient, K_d, with buffer content of the gel networks was found to hold only when the ratio of acryloylmorpholine to cross-linker was kept constant or was relatively high. Maximum molecular weight exclusion limit (> 2 × 10⁶ for dyed dextran) was observed at high cross-linker concentration.     

用MicroTCA机箱构建高性价比的硬件平台

作为当今业界流行的模块化硬件平台标准——AdvanedTCA标准的补充,MicroTCA硬件技术标准主要针对的是网络通信、医疗影像处理、嵌入式控制、军工等市场的中低端应用。其高带宽、模块化、灵活性、高性价比等优势使其能够被运用到较为广泛的应用领域,成为当今构建高性价比模块化标准硬件平台的优选标准。众所周知,MicroTCA平台中承载的是Advanced-MC（AMC）模块。     

Curriculum Materials Supporting Problem-Based Teaching

The vision for school mathematics described by the National Council of Teachers of Mathematics (NCTM) suggests a need for new approaches to the teaching and learning of mathematics, as well as new curriculum materials to support such change. This article discusses implications of the NCTM standards for mathematics curriculum and instruction and provides three examples of lessons from problem-based curricula for various grade levels. These examples illustrate how the teaching of important mathematics through student exploration of interesting problems might unfold, and they highlight the differences between a problem-based approach and more traditional approaches. Considerations for teaching through a problem-based approach are raised, as well as reflections on the potential impact on student learning.     

PHOTOBIOLOGY OF RNA BACTERIOPHAGES—I. ULTRAVIOLET INACTIVATION AND PHOTOREACTIVATION STUDIES*

Abstract— Biologically active f2-RNA, Obtained from bacteriophage f2, was inactivated by ultraviolet (u.v) light (2537 Å) with a quantum yield of 3.3 ± 0.3 times 10^-3 when assayed in the dark with protoplasts of an F- strain of E. coli k12. Assay under “black light” gave a quantum yield of 2.7 ± 0.5 times 10^-3 which was just enough lower to suggest that 17 per cent photorecovery of the u.v. lesions has taken place. Intact phage f2 was inactivated by u.v. radiation with a quantum yield of 0.7 ± 0.12 times 10^-3, Thus the whole phage is much less sensitive than the free RNA. No evidence of photorecovery was found in u.v.-irradiated RNA phage 7S assayed in its host Pseudomonas aeruginosa.     

Relational Communication and Understanding in Conversations About Hurtful Events Between Parents and Adolescents

This article examines how the severity of a hurtful event and discrepancies in perceptions of relational communication affect perceived understanding and empathic accuracy (EA) in parent–adolescent discussions about a hurtful event in their relationship. Results from a dyadic interaction study showed that the severity of the hurtful event was negatively associated with perceived understanding. Furthermore, discrepancies in perceptions of disaffiliation behaviors during a conversation about a child's hurtful event were also negatively associated with perceived understanding. Discrepancy in perceptions of adolescent's dominance corresponded negatively with parents' perceived understanding when discussing the child's hurtful event. There were no significant associations with EA. The implications for work on hurtful events, understanding, and relational framing theory are discussed.     

FTIR Emission Spectra, Molecular Constants, and Potential Curve of Ground State GeO

Extensive new high-temperature, high-resolution FTIR emission spectroscopy measurements for the five common isotopomers of GeO are combined with previous diode laser and microwave measurements in combined isotopomer analyses. New Dunham expansion parameters and an accurate analytical potential energy function are determined for the ground X1Sigma+ state. Copyright 1999 Academic Press.